Merge PR #95: You-might-like liked-entity fallback (#790)

golangci-lint v2 (CI-only; local is v1) flagged the field-by-field struct
literals — the fallback and you-might-like row types are identical, so convert
directly instead.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -60,9 +60,35 @@ jobs:
       ANDROID_KEY_ALIAS: ${{ secrets.ANDROID_KEY_ALIAS }}
       ANDROID_KEY_PASSWORD: ${{ secrets.ANDROID_KEYSTORE_PASSWORD }}
 
+    # Job outputs propagate the computed release version to image-release
+    # so the bundled sidecar file matches what's baked into the APK —
+    # otherwise the server would report a different version string than
+    # the installed client and the update banner could thrash.
+    outputs:
+      version_name: ${{ steps.ver.outputs.name }}
+      version_code: ${{ steps.ver.outputs.code }}
+
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          # fetch-depth: 0 retrieves full history; default shallow clone
+          # would return 1 for `git rev-list --count HEAD`, breaking the
+          # iteration suffix.
+          fetch-depth: 0
+
+      - name: Compute release version
+        id: ver
+        shell: bash
+        working-directory: ${{ github.workspace }}
+        run: |
+          set -euo pipefail
+          TAG="${GITHUB_REF#refs/tags/v}"
+          COMMIT_COUNT=$(git rev-list --count HEAD)
+          VERSION_NAME="${TAG}.${COMMIT_COUNT}"
+          echo "name=${VERSION_NAME}" >> "$GITHUB_OUTPUT"
+          echo "code=${COMMIT_COUNT}" >> "$GITHUB_OUTPUT"
+          echo "::notice::APK version: ${VERSION_NAME} (code=${COMMIT_COUNT})"
 
       - name: Cache Gradle dirs
         uses: actions/cache@v4
@@ -91,7 +117,10 @@ jobs:
           echo "ANDROID_KEYSTORE_PATH=${KEYSTORE_PATH}" >> "${GITHUB_ENV}"
 
       - name: Build release APK
-        run: ./gradlew assembleRelease
+        run: |
+          ./gradlew assembleRelease \
+            -PMINSTREL_VERSION_NAME=${{ steps.ver.outputs.name }} \
+            -PMINSTREL_VERSION_CODE=${{ steps.ver.outputs.code }}
 
       - name: Upload APK as workflow artifact
         # @v3 because Gitea Actions emulates GHES and the v2 artifact
@@ -204,14 +233,18 @@ jobs:
       - name: Stage bundled APK + version sidecar
         if: steps.guard.outputs.ready == 'true' && startsWith(github.ref, 'refs/tags/v')
         shell: bash
+        env:
+          # Pulled from android-release.outputs.version_name so the
+          # sidecar string the server hands clients matches the
+          # versionName baked into the APK they're comparing against.
+          APK_VERSION_NAME: ${{ needs.android-release.outputs.version_name }}
         run: |
           set -euxo pipefail
-          TAG="${GITHUB_REF#refs/tags/}"
           # The artifact lands as `app-release.apk` (the original Gradle
           # output name). The Dockerfile COPYs client/* into /app/client/
           # and the server reads minstrel.apk + minstrel.apk.version.
           mv client/app-release.apk client/minstrel.apk
-          echo "${TAG}" > client/minstrel.apk.version
+          echo "${APK_VERSION_NAME}" > client/minstrel.apk.version
           ls -lh client/
 
       - name: Build and push

.gitea/workflows/test-go.yml

@@ -116,6 +116,27 @@ jobs:
           # Wait for Postgres to accept TCP (no health-check dependency).
           for i in $(seq 1 60); do (echo > "/dev/tcp/${PG_IP}/5432") 2>/dev/null && break; sleep 2; done
 
+          # Relax durability on the throwaway CI Postgres. Our test pattern
+          # is dbtest.ResetDB → TRUNCATE … RESTART IDENTITY CASCADE before
+          # every test, and the per-TRUNCATE commit fsync is the dominant
+          # cost of the integration suite. The CI DB is rebuilt every run so
+          # fsync / full_page_writes / synchronous_commit buy nothing. Apply
+          # via docker exec because:
+          #  - The act_runner `services:` block can't override the container
+          #    command, so `postgres -c fsync=off` at boot isn't an option.
+          #  - ALTER SYSTEM cannot run inside a transaction; psql -c
+          #    auto-commits each statement, which is what we need.
+          #  - fsync / full_page_writes are sighup GUCs and
+          #    synchronous_commit is user-context, so pg_reload_conf() picks
+          #    all three up with no restart.
+          # Non-fatal: a perms surprise degrades to "slower", never red CI.
+          docker exec "$PG_ID" psql -U minstrel -d minstrel_test \
+            -c "ALTER SYSTEM SET fsync = off" \
+            -c "ALTER SYSTEM SET synchronous_commit = off" \
+            -c "ALTER SYSTEM SET full_page_writes = off" \
+            -c "SELECT pg_reload_conf()" \
+            || echo "WARN: durability relax failed; continuing"
+
           # Apply embedded migrations to the fresh test DB, then run the
           # full suite (no -short → integration tests execute). -p 1:
           # every integration package TRUNCATEs the one shared test DB;

android/.idea/caches/deviceStreaming.xml

@@ -1754,6 +1754,19 @@
           <option name="screenX" value="1600" />
           <option name="screenY" value="2560" />
         </PersistentDeviceSelectionData>
+        <PersistentDeviceSelectionData>
+          <option name="api" value="36" />
+          <option name="brand" value="google" />
+          <option name="codename" value="tangorpro" />
+          <option name="formFactor" value="Tablet" />
+          <option name="id" value="tangorpro" />
+          <option name="labId" value="google" />
+          <option name="manufacturer" value="Google" />
+          <option name="name" value="Pixel Tablet" />
+          <option name="screenDensity" value="320" />
+          <option name="screenX" value="1600" />
+          <option name="screenY" value="2560" />
+        </PersistentDeviceSelectionData>
         <PersistentDeviceSelectionData>
           <option name="api" value="35" />
           <option name="brand" value="google" />

android/.idea/misc.xml

@@ -1,4 +1,3 @@
-<?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ExternalStorageConfigurationManager" enabled="true" />
   <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="jbr-21" project-jdk-type="JavaSDK">

android/app/build.gradle.kts

@@ -21,8 +21,19 @@ android {
         applicationId = "com.fabledsword.minstrel"
         minSdk = 26
         targetSdk = 36
-        versionCode = 1
-        versionName = "0.1.0-native"
+        // versionName / versionCode are released-build values injected by
+        // CI from the git tag + commit count. Local / debug builds fall
+        // back to "dev" so the About card reads honestly. Releases ship
+        // versionName="YYYY.MM.DD.<commits>" (e.g. "2026.06.02.142") and
+        // versionCode=<commits>, which is monotonic forever and lets the
+        // shared isVersionNewer comparator distinguish two same-day
+        // re-cuts (the iteration suffix differs).
+        val versionNameOverride =
+            (project.findProperty("MINSTREL_VERSION_NAME") as String?)?.takeIf { it.isNotBlank() }
+        val versionCodeOverride =
+            (project.findProperty("MINSTREL_VERSION_CODE") as String?)?.toIntOrNull()
+        versionCode = versionCodeOverride ?: 1
+        versionName = versionNameOverride ?: "dev"
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
         vectorDrawables { useSupportLibrary = true }
     }
@@ -162,6 +173,7 @@ dependencies {
     implementation(libs.media3.exoplayer)
     implementation(libs.media3.session)
     implementation(libs.media3.datasource.okhttp)
+    implementation(libs.mediarouter)
 
     implementation(libs.coil.compose)
     implementation(libs.coil.network.okhttp)
@@ -175,6 +187,12 @@ dependencies {
     testImplementation(libs.mockk)
     testImplementation(libs.kotlinx.coroutines.test)
     testImplementation(libs.okhttp.mockwebserver)
+    // kxml2 — provides an org.xmlpull.v1 impl on the JVM unit-test
+    // classpath. Android's stock XmlPullParserFactory resolves to the
+    // android.jar Stub on JVM tests; kxml2 is picked up via service-
+    // provider lookup and makes XmlPullParserFactory.newInstance() work
+    // unconditionally so DeviceDescriptionTest runs in CI.
+    testImplementation(libs.kxml2)
     // kotlin.test for assertEquals/assertNull/etc. — version managed by
     // the applied Kotlin plugin so no explicit version pin needed.
     testImplementation(kotlin("test"))

android/app/schemas/com.fabledsword.minstrel.cache.db.AppDatabase/6.json

@@ -0,0 +1,690 @@
+{
+  "formatVersion": 1,
+  "database": {
+    "version": 6,
+    "identityHash": "fb73ed8674efb1d82a586551baba5ef0",
+    "entities": [
+      {
+        "tableName": "sync_metadata",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER NOT NULL, `cursor` INTEGER NOT NULL, `lastSyncAt` INTEGER, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "cursor",
+            "columnName": "cursor",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "lastSyncAt",
+            "columnName": "lastSyncAt",
+            "affinity": "INTEGER"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_artists",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` TEXT NOT NULL, `name` TEXT NOT NULL, `sortName` TEXT NOT NULL, `mbid` TEXT, `artistThumbPath` TEXT, `artistFanartPath` TEXT, `fetchedAt` INTEGER NOT NULL, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "name",
+            "columnName": "name",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "sortName",
+            "columnName": "sortName",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "mbid",
+            "columnName": "mbid",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "artistThumbPath",
+            "columnName": "artistThumbPath",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "artistFanartPath",
+            "columnName": "artistFanartPath",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "fetchedAt",
+            "columnName": "fetchedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_albums",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` TEXT NOT NULL, `artistId` TEXT NOT NULL, `title` TEXT NOT NULL, `sortTitle` TEXT NOT NULL, `releaseDate` TEXT, `coverPath` TEXT, `mbid` TEXT, `fetchedAt` INTEGER NOT NULL, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "artistId",
+            "columnName": "artistId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "title",
+            "columnName": "title",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "sortTitle",
+            "columnName": "sortTitle",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "releaseDate",
+            "columnName": "releaseDate",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "coverPath",
+            "columnName": "coverPath",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "mbid",
+            "columnName": "mbid",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "fetchedAt",
+            "columnName": "fetchedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_tracks",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` TEXT NOT NULL, `albumId` TEXT NOT NULL, `artistId` TEXT NOT NULL, `title` TEXT NOT NULL, `durationMs` INTEGER NOT NULL, `trackNumber` INTEGER, `discNumber` INTEGER, `filePath` TEXT, `fileFormat` TEXT, `genre` TEXT, `fetchedAt` INTEGER NOT NULL, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "albumId",
+            "columnName": "albumId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "artistId",
+            "columnName": "artistId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "title",
+            "columnName": "title",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "durationMs",
+            "columnName": "durationMs",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "trackNumber",
+            "columnName": "trackNumber",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "discNumber",
+            "columnName": "discNumber",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "filePath",
+            "columnName": "filePath",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "fileFormat",
+            "columnName": "fileFormat",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "genre",
+            "columnName": "genre",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "fetchedAt",
+            "columnName": "fetchedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_likes",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`userId` TEXT NOT NULL, `entityType` TEXT NOT NULL, `entityId` TEXT NOT NULL, `likedAt` INTEGER NOT NULL, PRIMARY KEY(`userId`, `entityType`, `entityId`))",
+        "fields": [
+          {
+            "fieldPath": "userId",
+            "columnName": "userId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "entityType",
+            "columnName": "entityType",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "entityId",
+            "columnName": "entityId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "likedAt",
+            "columnName": "likedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "userId",
+            "entityType",
+            "entityId"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_playlists",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` TEXT NOT NULL, `userId` TEXT NOT NULL, `name` TEXT NOT NULL, `description` TEXT NOT NULL, `isPublic` INTEGER NOT NULL, `coverPath` TEXT, `trackCount` INTEGER NOT NULL, `durationSec` INTEGER NOT NULL, `systemVariant` TEXT, `fetchedAt` INTEGER NOT NULL, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "userId",
+            "columnName": "userId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "name",
+            "columnName": "name",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "description",
+            "columnName": "description",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "isPublic",
+            "columnName": "isPublic",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "coverPath",
+            "columnName": "coverPath",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "trackCount",
+            "columnName": "trackCount",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "durationSec",
+            "columnName": "durationSec",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "systemVariant",
+            "columnName": "systemVariant",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "fetchedAt",
+            "columnName": "fetchedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_playlist_tracks",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`playlistId` TEXT NOT NULL, `trackId` TEXT NOT NULL, `position` INTEGER NOT NULL, PRIMARY KEY(`playlistId`, `trackId`))",
+        "fields": [
+          {
+            "fieldPath": "playlistId",
+            "columnName": "playlistId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "trackId",
+            "columnName": "trackId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "position",
+            "columnName": "position",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "playlistId",
+            "trackId"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_quarantine_mine",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`trackId` TEXT NOT NULL, `reason` TEXT NOT NULL, `notes` TEXT, `createdAt` TEXT NOT NULL, `trackTitle` TEXT NOT NULL, `trackDurationMs` INTEGER NOT NULL, `albumId` TEXT NOT NULL, `albumTitle` TEXT NOT NULL, `albumCoverArtPath` TEXT, `artistId` TEXT NOT NULL, `artistName` TEXT NOT NULL, `fetchedAt` INTEGER NOT NULL, PRIMARY KEY(`trackId`))",
+        "fields": [
+          {
+            "fieldPath": "trackId",
+            "columnName": "trackId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "reason",
+            "columnName": "reason",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "notes",
+            "columnName": "notes",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "createdAt",
+            "columnName": "createdAt",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "trackTitle",
+            "columnName": "trackTitle",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "trackDurationMs",
+            "columnName": "trackDurationMs",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "albumId",
+            "columnName": "albumId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "albumTitle",
+            "columnName": "albumTitle",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "albumCoverArtPath",
+            "columnName": "albumCoverArtPath",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "artistId",
+            "columnName": "artistId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "artistName",
+            "columnName": "artistName",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "fetchedAt",
+            "columnName": "fetchedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "trackId"
+          ]
+        }
+      },
+      {
+        "tableName": "audio_cache_index",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`trackId` TEXT NOT NULL, `path` TEXT NOT NULL, `sizeBytes` INTEGER NOT NULL, `cachedAt` INTEGER NOT NULL, `lastPlayedAt` INTEGER, `source` TEXT NOT NULL, PRIMARY KEY(`trackId`))",
+        "fields": [
+          {
+            "fieldPath": "trackId",
+            "columnName": "trackId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "path",
+            "columnName": "path",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "sizeBytes",
+            "columnName": "sizeBytes",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "cachedAt",
+            "columnName": "cachedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "lastPlayedAt",
+            "columnName": "lastPlayedAt",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "source",
+            "columnName": "source",
+            "affinity": "TEXT",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "trackId"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_mutations",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, `kind` TEXT NOT NULL, `payload` TEXT NOT NULL, `createdAt` INTEGER NOT NULL, `lastAttemptAt` INTEGER, `attempts` INTEGER NOT NULL)",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "kind",
+            "columnName": "kind",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "payload",
+            "columnName": "payload",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "createdAt",
+            "columnName": "createdAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "lastAttemptAt",
+            "columnName": "lastAttemptAt",
+            "affinity": "INTEGER"
+          },
+          {
+            "fieldPath": "attempts",
+            "columnName": "attempts",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": true,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_resume_state",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER NOT NULL, `json` TEXT NOT NULL, `updatedAt` INTEGER NOT NULL, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "json",
+            "columnName": "json",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "updatedAt",
+            "columnName": "updatedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_home_index",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`section` TEXT NOT NULL, `position` INTEGER NOT NULL, `entityType` TEXT NOT NULL, `entityId` TEXT NOT NULL, `fetchedAt` INTEGER NOT NULL, PRIMARY KEY(`section`, `position`))",
+        "fields": [
+          {
+            "fieldPath": "section",
+            "columnName": "section",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "position",
+            "columnName": "position",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "entityType",
+            "columnName": "entityType",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "entityId",
+            "columnName": "entityId",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "fetchedAt",
+            "columnName": "fetchedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "section",
+            "position"
+          ]
+        }
+      },
+      {
+        "tableName": "cached_history_snapshot",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER NOT NULL, `json` TEXT NOT NULL, `updatedAt` INTEGER NOT NULL, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "json",
+            "columnName": "json",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "updatedAt",
+            "columnName": "updatedAt",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      },
+      {
+        "tableName": "auth_session",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER NOT NULL, `sessionCookie` TEXT, `baseUrl` TEXT NOT NULL, `userJson` TEXT, `themeMode` TEXT, `clientId` TEXT, `cacheSettingsJson` TEXT, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "sessionCookie",
+            "columnName": "sessionCookie",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "baseUrl",
+            "columnName": "baseUrl",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "userJson",
+            "columnName": "userJson",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "themeMode",
+            "columnName": "themeMode",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "clientId",
+            "columnName": "clientId",
+            "affinity": "TEXT"
+          },
+          {
+            "fieldPath": "cacheSettingsJson",
+            "columnName": "cacheSettingsJson",
+            "affinity": "TEXT"
+          }
+        ],
+        "primaryKey": {
+          "autoGenerate": false,
+          "columnNames": [
+            "id"
+          ]
+        }
+      }
+    ],
+    "setupQueries": [
+      "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, 'fb73ed8674efb1d82a586551baba5ef0')"
+    ]
+  }
+}

android/app/src/main/AndroidManifest.xml

@@ -9,6 +9,8 @@
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PLAYBACK" />
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
     <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />
+    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
+    <uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
 
     <application
         android:name=".MinstrelApplication"
@@ -22,9 +24,14 @@
         android:usesCleartextTraffic="true"
         tools:targetApi="34">
 
+        <!-- Portrait-locked until a tablet/landscape layout exists.
+             Current Compose screens are sized for phone-portrait;
+             landscape just stretches the column awkwardly. Revisit
+             this when a dedicated tablet layout lands. -->
         <activity
             android:name=".MainActivity"
             android:exported="true"
+            android:screenOrientation="portrait"
             android:theme="@style/Theme.Minstrel">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />

android/app/src/main/java/com/fabledsword/minstrel/MainActivity.kt

@@ -1,5 +1,6 @@
 package com.fabledsword.minstrel
 
+import android.content.Intent
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
@@ -11,6 +12,7 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -19,24 +21,69 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation.compose.rememberNavController
 import com.fabledsword.minstrel.auth.ui.AuthGateViewModel
 import com.fabledsword.minstrel.cache.CachedTrackIds
+import com.fabledsword.minstrel.connectivity.LocalServerHealth
+import com.fabledsword.minstrel.connectivity.ServerHealth
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
 import com.fabledsword.minstrel.nav.DetailSeedCache
 import com.fabledsword.minstrel.nav.LocalDetailSeedCache
 import com.fabledsword.minstrel.nav.MinstrelNavGraph
+import com.fabledsword.minstrel.nav.NowPlaying
 import com.fabledsword.minstrel.shared.widgets.LocalCachedTrackIds
 import com.fabledsword.minstrel.theme.MinstrelTheme
 import com.fabledsword.minstrel.theme.ThemePreferenceViewModel
 import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
 import javax.inject.Inject
 
 @AndroidEntryPoint
 class MainActivity : ComponentActivity() {
     @Inject lateinit var seedCache: DetailSeedCache
     @Inject lateinit var cachedTrackIds: CachedTrackIds
+    @Inject lateinit var serverHealth: NetworkStatusController
+
+    // Flipped to true when the user taps the media notification (or
+    // any other entry point that asks for the full player). The App
+    // composable observes this, navigates to NowPlaying once the
+    // NavHost is ready, then calls back to reset the flag so the
+    // navigation doesn't re-fire on the next recomposition.
+    private val pendingOpenNowPlaying = MutableStateFlow(false)
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         enableEdgeToEdge()
-        setContent { App(seedCache = seedCache, cachedTrackIds = cachedTrackIds) }
+        consumeOpenNowPlayingIntent(intent)
+        setContent {
+            App(
+                seedCache = seedCache,
+                cachedTrackIds = cachedTrackIds,
+                serverHealth = serverHealth,
+                pendingOpenNowPlaying = pendingOpenNowPlaying.asStateFlow(),
+                onOpenedNowPlaying = { pendingOpenNowPlaying.value = false },
+            )
+        }
+    }
+
+    override fun onNewIntent(intent: Intent) {
+        super.onNewIntent(intent)
+        consumeOpenNowPlayingIntent(intent)
+    }
+
+    private fun consumeOpenNowPlayingIntent(intent: Intent?) {
+        if (intent?.getBooleanExtra(EXTRA_OPEN_NOW_PLAYING, false) == true) {
+            pendingOpenNowPlaying.value = true
+            // Strip the extra so a subsequent config-change recreation
+            // doesn't re-trigger the navigation.
+            intent.removeExtra(EXTRA_OPEN_NOW_PLAYING)
+        }
+    }
+
+    companion object {
+        /** PendingIntent extra set by [com.fabledsword.minstrel.player.MinstrelPlayerService]
+         *  so a media-notification tap lands on the full NowPlaying screen
+         *  instead of whatever shell route MainActivity last rendered. */
+        const val EXTRA_OPEN_NOW_PLAYING = "com.fabledsword.minstrel.action.OPEN_NOW_PLAYING"
     }
 }
 
@@ -44,15 +91,21 @@ class MainActivity : ComponentActivity() {
 private fun App(
     seedCache: DetailSeedCache,
     cachedTrackIds: CachedTrackIds,
+    serverHealth: NetworkStatusController,
+    pendingOpenNowPlaying: StateFlow<Boolean>,
+    onOpenedNowPlaying: () -> Unit,
     themeVm: ThemePreferenceViewModel = hiltViewModel(),
     gate: AuthGateViewModel = hiltViewModel(),
 ) {
     val theme by themeVm.themeMode.collectAsStateWithLifecycle()
     val cached by cachedTrackIds.ids.collectAsStateWithLifecycle()
+    val health: ServerHealth by serverHealth.state.collectAsStateWithLifecycle()
+    val pending by pendingOpenNowPlaying.collectAsStateWithLifecycle()
     MinstrelTheme(darkOverride = theme.toDarkOverride()) {
         CompositionLocalProvider(
             LocalDetailSeedCache provides seedCache,
             LocalCachedTrackIds provides cached,
+            LocalServerHealth provides health,
         ) {
             val startDestination by gate.startDestination.collectAsStateWithLifecycle()
             val resolved = startDestination
@@ -65,6 +118,18 @@ private fun App(
                 // `ShellScaffold` wrap; full-screen routes (NowPlaying /
                 // Queue / unauthenticated) bypass the shell entirely.
                 val navController = rememberNavController()
+                // Honour a pending notification-tap once the NavHost is
+                // mounted. launchSingleTop avoids stacking copies of
+                // NowPlaying if the user taps the notification while
+                // already on it; the callback clears the flag so a later
+                // recomposition (config change, theme switch) doesn't
+                // re-navigate.
+                LaunchedEffect(pending, navController) {
+                    if (pending) {
+                        navController.navigate(NowPlaying) { launchSingleTop = true }
+                        onOpenedNowPlaying()
+                    }
+                }
                 MinstrelNavGraph(
                     navController = navController,
                     startDestination = resolved,

android/app/src/main/java/com/fabledsword/minstrel/MinstrelApplication.kt

@@ -19,7 +19,7 @@ import com.fabledsword.minstrel.player.PlayEventsReporter
 import com.fabledsword.minstrel.player.PlaybackErrorReporter
 import com.fabledsword.minstrel.player.ResumeController
 import com.fabledsword.minstrel.update.data.UpdateBannerController
-import com.fabledsword.minstrel.update.data.VersionCheckController
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
 import dagger.hilt.android.HiltAndroidApp
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.launch
@@ -114,12 +114,13 @@ class MinstrelApplication :
     @Suppress("unused") @Inject lateinit var audioPrefetcher: AudioPrefetcher
 
     /**
-     * Same construct-the-singleton trick — VersionCheckController's
-     * init block starts a 5-min poll loop against /healthz so the
-     * shell-level VersionTooOldBanner can surface min_client_version
-     * mismatches without waiting for the next user-driven request.
+     * Same construct-the-singleton trick — NetworkStatusController owns the
+     * /healthz poll loop + the device-link collector + the reachability state
+     * machine, and is the single authority on the tri-state ServerHealth
+     * signal (plus the VersionTooOld byproduct). It must exist from launch so
+     * the poll loop runs and the StateFlow stays warm for every consumer.
      */
-    @Suppress("unused") @Inject lateinit var versionCheckController: VersionCheckController
+    @Suppress("unused") @Inject lateinit var networkStatusController: NetworkStatusController
 
     /**
      * Same construct-the-singleton trick — UpdateBannerController polls
@@ -158,10 +159,43 @@ class MinstrelApplication :
 
     override fun onCreate() {
         super.onCreate()
-        if (BuildConfig.DEBUG) Timber.plant(Timber.DebugTree())
+        // Debug builds get the full DebugTree (verbose). Release builds
+        // get a WARN+ tree so operator-driven diagnosis via `adb logcat`
+        // still surfaces UPnP / cast failures, OkHttp errors, and our
+        // own Timber.w / Timber.e calls — without the chatty DEBUG /
+        // INFO traffic flooding the buffer in production.
+        if (BuildConfig.DEBUG) {
+            Timber.plant(Timber.DebugTree())
+        } else {
+            Timber.plant(ReleaseTree())
+        }
         appScope.launch { resumeController.restore() }
     }
 
+    /**
+     * Release-build Timber tree: emits at WARN and above only.
+     * `android.util.Log` with the canonical tag so `adb logcat` shows
+     * the line under the standard tag column without falling through
+     * to the package-stack-trace tag DebugTree produces.
+     */
+    private class ReleaseTree : Timber.Tree() {
+        override fun isLoggable(tag: String?, priority: Int): Boolean =
+            priority >= android.util.Log.WARN
+
+        override fun log(priority: Int, tag: String?, message: String, t: Throwable?) {
+            val resolvedTag = tag ?: "Minstrel"
+            if (t == null) {
+                android.util.Log.println(priority, resolvedTag, message)
+            } else {
+                android.util.Log.println(
+                    priority,
+                    resolvedTag,
+                    message + '\n' + android.util.Log.getStackTraceString(t),
+                )
+            }
+        }
+    }
+
     override val workManagerConfiguration: Configuration
         get() = Configuration.Builder()
             .setWorkerFactory(workerFactory)

android/app/src/main/java/com/fabledsword/minstrel/api/AuthCookieInterceptor.kt

@@ -7,11 +7,23 @@ import javax.inject.Inject
 import javax.inject.Singleton
 
 /**
- * Attaches the session cookie from [AuthStore] to every request,
- * captures Set-Cookie from successful responses (login flow), and
- * clears the store on 401 so downstream code can react to logout.
+ * Attaches the session cookie from [AuthStore] to Minstrel-server
+ * requests, captures Set-Cookie from successful responses (login
+ * flow), and clears the store on 401 so downstream code can react
+ * to logout.
  *
  * Mirrors the Flutter Dio interceptor pattern.
+ *
+ * Scoped to the [BaseUrlInterceptor.PLACEHOLDER_HOST] sentinel host
+ * the same way BaseUrlInterceptor is. Drift #568 / #569 caught two
+ * leaks here: (1) the session cookie was being attached to every
+ * external request the shared OkHttpClient services — including
+ * Coil image fetches to artwork.musicbrainz.org / coverartarchive.org
+ * / Lidarr's /MediaCover endpoints — exposing the session
+ * identifier to third-party logging; (2) a 401 from any of those
+ * external hosts silently wiped the user's Minstrel session.
+ * Restricting both attach + clear to placeholder-host requests
+ * closes both gaps.
  */
 @Singleton
 class AuthCookieInterceptor @Inject constructor(
@@ -19,8 +31,15 @@ class AuthCookieInterceptor @Inject constructor(
 ) : Interceptor {
 
     override fun intercept(chain: Interceptor.Chain): Response {
+        val original = chain.request()
+        if (original.url.host != BaseUrlInterceptor.PLACEHOLDER_HOST) {
+            // External request — no Minstrel session cookie attached,
+            // and a 401 from this host does NOT clear the user's
+            // session. Pass through untouched.
+            return chain.proceed(original)
+        }
         val cookie = authStore.sessionCookie.value
-        val request = chain.request().newBuilder().apply {
+        val request = original.newBuilder().apply {
             if (!cookie.isNullOrEmpty()) header("Cookie", cookie)
         }.build()
 

android/app/src/main/java/com/fabledsword/minstrel/api/BaseUrlInterceptor.kt

@@ -9,16 +9,23 @@ import javax.inject.Inject
 import javax.inject.Singleton
 
 /**
- * Rewrites every outgoing request's scheme/host/port to match the
+ * Rewrites Minstrel-server requests' scheme/host/port to match the
  * current [AuthStore.baseUrl]. Retrofit's `.baseUrl(...)` is read
  * once at Retrofit creation, but AuthStore.baseUrl loads from Room
  * asynchronously — so at injection time the Retrofit instance is
  * frozen pointing at the [AuthStore.DEFAULT_BASE_URL] placeholder.
  *
  * This interceptor closes the gap: Retrofit can stay built with the
- * placeholder forever, and every actual request gets retargeted at
- * the live AuthStore value. Lets the user change server URL in
- * Settings without an app relaunch (Phase 11 wiring).
+ * placeholder forever, and every actual Minstrel-bound request gets
+ * retargeted at the live AuthStore value. Lets the user change
+ * server URL in Settings without an app relaunch (Phase 11 wiring).
+ *
+ * Only requests whose host is the [PLACEHOLDER_HOST] sentinel are
+ * rewritten. Absolute external URLs — Lidarr-surfaced artwork from
+ * artwork.musicbrainz.org / coverartarchive.org, for example — must
+ * reach their authored host unchanged; rewriting them to the
+ * Minstrel host produced 404s the user saw as missing Discover
+ * suggestion covers.
  *
  * No-op when the stored base URL is unparseable (falls through to
  * whatever Retrofit had) — that case shows up as a transport-level
@@ -31,13 +38,26 @@ class BaseUrlInterceptor @Inject constructor(
 
     override fun intercept(chain: Interceptor.Chain): Response {
         val original = chain.request()
-        val baseUrl = authStore.baseUrl.value.toHttpUrlOrNull()
-            ?: return chain.proceed(original)
-        val rewritten: HttpUrl = original.url.newBuilder()
-            .scheme(baseUrl.scheme)
-            .host(baseUrl.host)
-            .port(baseUrl.port)
-            .build()
+        // Early-bail keeps the no-op path for external URLs cheap
+        // (no AuthStore read, no URL parse).
+        if (original.url.host != PLACEHOLDER_HOST) return chain.proceed(original)
+        // Unparseable baseUrl folds into the same proceed path — keeps
+        // detekt's ReturnCount happy by avoiding a second early return.
+        val rewritten: HttpUrl = authStore.baseUrl.value.toHttpUrlOrNull()?.let { baseUrl ->
+            original.url.newBuilder()
+                .scheme(baseUrl.scheme)
+                .host(baseUrl.host)
+                .port(baseUrl.port)
+                .build()
+        } ?: original.url
         return chain.proceed(original.newBuilder().url(rewritten).build())
     }
+
+    companion object {
+        /** Sentinel host used by Retrofit + every code path that builds
+         *  a Minstrel-server URL via the `http://placeholder.invalid/...`
+         *  form (see [com.fabledsword.minstrel.shared.resolveServerUrl],
+         *  CoverUrls.kt, AlbumRef/TrackRef cover getters). */
+        const val PLACEHOLDER_HOST = "placeholder.invalid"
+    }
 }

android/app/src/main/java/com/fabledsword/minstrel/api/NetworkModule.kt

@@ -1,6 +1,7 @@
 package com.fabledsword.minstrel.api
 
 import com.fabledsword.minstrel.BuildConfig
+import com.fabledsword.minstrel.connectivity.ReachabilityReportingInterceptor
 import com.jakewharton.retrofit2.converter.kotlinx.serialization.asConverterFactory
 import dagger.Module
 import dagger.Provides
@@ -45,14 +46,29 @@ object NetworkModule {
     fun provideOkHttp(
         baseUrl: BaseUrlInterceptor,
         auth: AuthCookieInterceptor,
+        reachability: ReachabilityReportingInterceptor,
         logging: HttpLoggingInterceptor,
     ): OkHttpClient =
         OkHttpClient.Builder()
-            // BaseUrlInterceptor first — it rewrites scheme/host/port
-            // to match the live AuthStore.baseUrl on every request.
-            // Auth then sees the final URL.
-            .addInterceptor(baseUrl)
+            // ReachabilityReportingInterceptor MUST run first: it identifies
+            // Minstrel-bound requests by the still-unrewritten PLACEHOLDER_HOST
+            // (so external artwork fetches don't read as server reachability)
+            // and observes the final transport outcome by wrapping the chain.
+            .addInterceptor(reachability)
+            // AuthCookieInterceptor MUST run before BaseUrlInterceptor.
+            // Both scope on `host == PLACEHOLDER_HOST` to distinguish
+            // Minstrel-server requests from external image fetches
+            // (drift #568 / #569). If BaseUrlInterceptor runs first it
+            // rewrites the host to the real server before auth sees the
+            // request, auth's placeholder check fails, and the session
+            // cookie is neither attached on outgoing requests nor
+            // captured from Set-Cookie on login — fresh installs get
+            // stuck at the Welcome screen. Auth first means it sees
+            // placeholder.invalid, attaches/captures correctly, then
+            // BaseUrlInterceptor retargets to the live AuthStore host
+            // for transport.
             .addInterceptor(auth)
+            .addInterceptor(baseUrl)
             .addInterceptor(logging)
             .connectTimeout(CONNECT_TIMEOUT_SECONDS, TimeUnit.SECONDS)
             .readTimeout(READ_TIMEOUT_SECONDS, TimeUnit.SECONDS)

android/app/src/main/java/com/fabledsword/minstrel/api/endpoints/CastApi.kt

@@ -0,0 +1,56 @@
+package com.fabledsword.minstrel.api.endpoints
+
+import kotlinx.serialization.Serializable
+import retrofit2.http.Body
+import retrofit2.http.POST
+
+/**
+ * Retrofit interface for the cast-token endpoint. Used by the UPnP
+ * selection path in `OutputPickerController` to obtain a signed stream
+ * URL that a network speaker can fetch without the user's session
+ * cookie — those devices cannot carry the session, so the signed
+ * query string is the only way they can fetch the bytes.
+ *
+ * Endpoint: `POST /api/cast/stream-token`
+ * Auth: standard session cookie (`AuthCookieInterceptor` handles it).
+ *
+ * Server contract lives at `internal/api/cast_token.go`
+ * (commit e774097f). Field names here mirror the server's `json:`
+ * tags verbatim — `trackId` / `expSeconds` — so no `@SerialName` is
+ * needed on the request, and `token` / `exp` / `url` map straight
+ * through on the response.
+ */
+interface CastApi {
+    @POST("api/cast/stream-token")
+    suspend fun streamToken(@Body req: StreamTokenRequest): StreamTokenResponse
+}
+
+/**
+ * Request body. [expSeconds] is clamped server-side to [60, 86400];
+ * the 21_600 default (6h) is long enough to play through any typical
+ * track without re-minting mid-playback.
+ */
+@Serializable
+data class StreamTokenRequest(
+    val trackId: String,
+    val expSeconds: Int = 21_600,
+)
+
+/**
+ * Response body. [url] is a fully-formed stream URL with [token] and
+ * [exp] already embedded as query params — callers pass it verbatim
+ * to `AVTransport.SetAVTransportURI`. [mime] + [title] are the bits
+ * the client needs to build DIDL-Lite metadata for that call: Sonos
+ * rejects empty DIDL with vendor error 1023, so the server hands back
+ * the track's MIME (from `tracks.file_format`) and title so the
+ * client can populate `<res protocolInfo>` and `<dc:title>` without
+ * a follow-up round trip.
+ */
+@Serializable
+data class StreamTokenResponse(
+    val token: String,
+    val exp: Long,
+    val url: String,
+    val mime: String = "audio/mpeg",
+    val title: String = "",
+)

android/app/src/main/java/com/fabledsword/minstrel/api/endpoints/LibraryApi.kt

@@ -2,6 +2,7 @@ package com.fabledsword.minstrel.api.endpoints
 
 import com.fabledsword.minstrel.models.wire.AlbumDetailWire
 import com.fabledsword.minstrel.models.wire.ArtistDetailWire
+import com.fabledsword.minstrel.models.wire.ArtistWire
 import com.fabledsword.minstrel.models.wire.TrackWire
 import retrofit2.http.GET
 import retrofit2.http.Path
@@ -35,9 +36,26 @@ interface LibraryApi {
     @GET("api/artists/{id}/tracks")
     suspend fun getArtistTracks(@Path("id") id: String): List<TrackWire>
 
+    @GET("api/artists/{id}/similar")
+    suspend fun getSimilarArtists(
+        @Path("id") id: String,
+        @Query("limit") limit: Int = SIMILAR_ARTISTS_LIMIT,
+    ): List<ArtistWire>
+
+    @GET("api/artists/{id}/top-tracks")
+    suspend fun getArtistTopTracks(
+        @Path("id") id: String,
+        @Query("limit") limit: Int = TOP_TRACKS_LIMIT,
+    ): List<TrackWire>
+
     @GET("api/albums/{id}")
     suspend fun getAlbumDetail(@Path("id") id: String): AlbumDetailWire
 
     @GET("api/library/shuffle")
     suspend fun shuffleLibrary(@Query("limit") limit: Int = 100): List<TrackWire>
+
+    private companion object {
+        const val SIMILAR_ARTISTS_LIMIT = 12
+        const val TOP_TRACKS_LIMIT = 5
+    }
 }

android/app/src/main/java/com/fabledsword/minstrel/api/endpoints/PlaybackErrorsApi.kt

@@ -0,0 +1,33 @@
+package com.fabledsword.minstrel.api.endpoints
+
+import retrofit2.http.Body
+import retrofit2.http.POST
+
+/**
+ * Retrofit interface for `POST /api/playback-errors`. Reports a
+ * client-detected playback failure (zero-duration, decode error, ...)
+ * so the admin inbox surfaces it.
+ *
+ * Failures during dispatch are reported via the MutationQueue path
+ * for offline replay (see [com.fabledsword.minstrel.cache.mutations.MutationQueue.enqueuePlaybackErrorReport]).
+ */
+interface PlaybackErrorsApi {
+    @POST("api/playback-errors")
+    suspend fun report(@Body body: PlaybackErrorReportRequest)
+}
+
+/**
+ * POST body for `/api/playback-errors`. `kind` is one of
+ * "zero_duration" / "load_failed" / "stalled"; server validates against
+ * the CHECK constraint enum. `detail` is optional free-text (Media3
+ * error message, etc.). `clientId` reuses the existing playback
+ * client identifier the device already sends with `/api/plays/...`
+ * so support can correlate reports across surfaces.
+ */
+@kotlinx.serialization.Serializable
+data class PlaybackErrorReportRequest(
+    @kotlinx.serialization.SerialName("track_id") val trackId: String,
+    val kind: String,
+    val detail: String? = null,
+    @kotlinx.serialization.SerialName("client_id") val clientId: String,
+)

android/app/src/main/java/com/fabledsword/minstrel/cache/db/dao/CachedAlbumDao.kt

@@ -24,6 +24,14 @@ interface CachedAlbumDao {
     @Query("SELECT * FROM cached_albums WHERE id = :id")
     fun observeById(id: String): Flow<CachedAlbumEntity?>
 
+    @Query(
+        "SELECT * FROM cached_albums " +
+            "WHERE title LIKE '%' || :q || '%' COLLATE NOCASE " +
+            "ORDER BY sortTitle COLLATE NOCASE ASC " +
+            "LIMIT :limit",
+    )
+    suspend fun searchByTitle(q: String, limit: Int): List<CachedAlbumEntity>
+
     @Query("SELECT id FROM cached_albums WHERE fetchedAt < :before LIMIT :limit")
     suspend fun idsStaleBefore(before: Long, limit: Int): List<String>
 

android/app/src/main/java/com/fabledsword/minstrel/cache/db/dao/CachedArtistDao.kt

@@ -18,6 +18,14 @@ interface CachedArtistDao {
     @Query("SELECT * FROM cached_artists WHERE id = :id")
     fun observeById(id: String): Flow<CachedArtistEntity?>
 
+    @Query(
+        "SELECT * FROM cached_artists " +
+            "WHERE name LIKE '%' || :q || '%' COLLATE NOCASE " +
+            "ORDER BY sortName COLLATE NOCASE ASC " +
+            "LIMIT :limit",
+    )
+    suspend fun searchByName(q: String, limit: Int): List<CachedArtistEntity>
+
     @Query("SELECT id FROM cached_artists WHERE fetchedAt < :before LIMIT :limit")
     suspend fun idsStaleBefore(before: Long, limit: Int): List<String>
 

android/app/src/main/java/com/fabledsword/minstrel/cache/db/dao/CachedLikeDao.kt

@@ -4,6 +4,7 @@ import androidx.room.Dao
 import androidx.room.Insert
 import androidx.room.OnConflictStrategy
 import androidx.room.Query
+import androidx.room.Transaction
 import com.fabledsword.minstrel.cache.db.entities.CachedLikeEntity
 import kotlinx.coroutines.flow.Flow
 
@@ -36,4 +37,21 @@ interface CachedLikeDao {
             "WHERE userId = :userId AND entityType = :entityType AND entityId = :entityId",
     )
     suspend fun delete(userId: String, entityType: String, entityId: String)
+
+    @Query("DELETE FROM cached_likes WHERE userId = :userId")
+    suspend fun clearForUser(userId: String)
+
+    /**
+     * Atomically replaces the user's entire cached_likes set with
+     * [rows]. Used by [com.fabledsword.minstrel.likes.data.LikesRepository.refreshIds]
+     * so cross-device unlikes (a row that the server no longer
+     * surfaces) get removed from the local cache — drift #570
+     * caught the missing delete pass that left stale Liked tab
+     * entries pointing at tracks the user had unliked elsewhere.
+     */
+    @Transaction
+    suspend fun replaceAllForUser(userId: String, rows: List<CachedLikeEntity>) {
+        clearForUser(userId)
+        upsertAll(rows)
+    }
 }

android/app/src/main/java/com/fabledsword/minstrel/cache/db/dao/CachedPlaylistDao.kt

@@ -31,6 +31,20 @@ interface CachedPlaylistDao {
     @Query("SELECT * FROM cached_playlists WHERE id = :id")
     suspend fun getById(id: String): CachedPlaylistEntity?
 
+    /**
+     * Per-playlist count of member tracks resident in the audio cache index.
+     * LEFT JOINs so playlists with zero cached tracks still appear
+     * (cachedCount = 0). Drives the offline "fully cached" greying.
+     */
+    @Query(
+        "SELECT p.id AS playlistId, COUNT(a.trackId) AS cachedCount " +
+            "FROM cached_playlists p " +
+            "LEFT JOIN cached_playlist_tracks t ON t.playlistId = p.id " +
+            "LEFT JOIN audio_cache_index a ON a.trackId = t.trackId " +
+            "GROUP BY p.id",
+    )
+    fun observeCachedCounts(): Flow<List<PlaylistCachedCount>>
+
     @Insert(onConflict = OnConflictStrategy.REPLACE)
     suspend fun upsertAll(rows: List<CachedPlaylistEntity>)
 

android/app/src/main/java/com/fabledsword/minstrel/cache/db/dao/CachedTrackDao.kt

@@ -24,6 +24,14 @@ interface CachedTrackDao {
     @Query("SELECT * FROM cached_tracks WHERE id IN (:ids)")
     suspend fun getByIds(ids: List<String>): List<CachedTrackEntity>
 
+    @Query(
+        "SELECT * FROM cached_tracks " +
+            "WHERE title LIKE '%' || :q || '%' COLLATE NOCASE " +
+            "ORDER BY title COLLATE NOCASE ASC " +
+            "LIMIT :limit",
+    )
+    suspend fun searchByTitle(q: String, limit: Int): List<CachedTrackEntity>
+
     @Query("SELECT id FROM cached_tracks WHERE fetchedAt < :before LIMIT :limit")
     suspend fun idsStaleBefore(before: Long, limit: Int): List<String>
 

android/app/src/main/java/com/fabledsword/minstrel/cache/db/dao/PlaylistCachedCount.kt

@@ -0,0 +1,11 @@
+package com.fabledsword.minstrel.cache.db.dao
+
+/**
+ * Projection: how many of a playlist's member tracks are resident in the audio
+ * cache index. Backs the offline "fully cached" greying — a playlist is fully
+ * available offline when [cachedCount] reaches its `trackCount`.
+ */
+data class PlaylistCachedCount(
+    val playlistId: String,
+    val cachedCount: Int,
+)

android/app/src/main/java/com/fabledsword/minstrel/cache/db/entities/CachedHomeIndexEntity.kt

@@ -14,6 +14,11 @@ import kotlinx.datetime.Instant
  *   - "rediscover_artists"
  *   - "most_played_tracks"
  *   - "last_played_artists"
+ *   - "you_might_like_albums"
+ *   - "you_might_like_artists"
+ *
+ * New `section` values need no schema change — the column stores the
+ * string verbatim and the DAO keys on it.
  *
  * `entityType` is "album" | "artist" | "track" — dispatches hydration
  * to the right per-entity endpoint when a tile is rendered.

android/app/src/main/java/com/fabledsword/minstrel/cache/mutations/MutationQueue.kt

@@ -2,12 +2,18 @@ package com.fabledsword.minstrel.cache.mutations
 
 import com.fabledsword.minstrel.cache.db.dao.CachedMutationDao
 import com.fabledsword.minstrel.cache.db.entities.CachedMutationEntity
+import kotlinx.coroutines.channels.BufferOverflow
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.SharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.encodeToString
 import kotlinx.serialization.json.Json
 import javax.inject.Inject
 import javax.inject.Singleton
 
+private const val QUEUED_MESSAGE = "Saved — will sync when online"
+
 /**
  * Stable mutation kinds the queue knows how to replay. Strings are
  * persisted in `cached_mutations.kind` so renaming a variant breaks
@@ -21,6 +27,14 @@ object MutationKind {
     const val QUARANTINE_FLAG: String = "quarantine_flag"
     const val PLAY_OFFLINE: String = "play_offline"
     const val REQUEST_CANCEL: String = "request_cancel"
+    const val PLAYBACK_ERROR_REPORT: String = "playback_error_report"
+
+    // Durable close-by-id for a play whose server row is already open
+    // (play_started succeeded). Distinct from PLAY_OFFLINE, which records
+    // a *whole* play when no server row exists. Using close-by-id on
+    // background avoids the duplicate + orphan row the old offline-on-stop
+    // path produced (see 2026-06-11 contract audit).
+    const val PLAY_ENDED: String = "play_ended"
 }
 
 /**
@@ -70,47 +84,59 @@ class MutationQueue @Inject constructor(
     private val dao: CachedMutationDao,
     private val json: Json,
 ) {
+    // capacity=1 DROP_OLDEST so a burst of user enqueues (e.g. liking N
+    // tracks while offline) surfaces as one snackbar rather than queueing
+    // N. replay=0 because a hint observed at enqueue time isn't useful
+    // to a screen that mounts later.
+    private val _userEnqueueHints = MutableSharedFlow<String>(
+        replay = 0,
+        extraBufferCapacity = 1,
+        onBufferOverflow = BufferOverflow.DROP_OLDEST,
+    )
+
+    /**
+     * Hint stream consumed by [com.fabledsword.minstrel.shared.widgets.ShellScaffold]
+     * to surface "Saved — will sync when online" as a snackbar whenever a
+     * user-driven write hits the offline-fallback path. Background-only
+     * enqueues (play-events, playback-error reports) do not emit — those
+     * fire from non-foreground paths where a snackbar would be either
+     * dropped (no shell mounted) or jarring (lock-screen toggle).
+     */
+    val userEnqueueHints: SharedFlow<String> = _userEnqueueHints.asSharedFlow()
+
     suspend fun enqueueLikeToggle(
         entityType: String,
         entityId: String,
         desiredState: Boolean,
-    ): Long = dao.insert(
-        CachedMutationEntity(
-            kind = MutationKind.LIKE_TOGGLE,
-            payload = json.encodeToString(
-                LikeTogglePayload.serializer(),
-                LikeTogglePayload(entityType, entityId, desiredState),
-            ),
+    ): Long = insertUserDriven(
+        MutationKind.LIKE_TOGGLE,
+        json.encodeToString(
+            LikeTogglePayload.serializer(),
+            LikeTogglePayload(entityType, entityId, desiredState),
         ),
     )
 
-    suspend fun enqueueRequestCreate(payload: RequestCreatePayload): Long = dao.insert(
-        CachedMutationEntity(
-            kind = MutationKind.REQUEST_CREATE,
-            payload = json.encodeToString(RequestCreatePayload.serializer(), payload),
-        ),
+    suspend fun enqueueRequestCreate(payload: RequestCreatePayload): Long = insertUserDriven(
+        MutationKind.REQUEST_CREATE,
+        json.encodeToString(RequestCreatePayload.serializer(), payload),
     )
 
-    suspend fun enqueueQuarantineUnflag(trackId: String): Long = dao.insert(
-        CachedMutationEntity(
-            kind = MutationKind.QUARANTINE_UNFLAG,
-            payload = json.encodeToString(
-                QuarantineUnflagPayload.serializer(),
-                QuarantineUnflagPayload(trackId),
-            ),
+    suspend fun enqueueQuarantineUnflag(trackId: String): Long = insertUserDriven(
+        MutationKind.QUARANTINE_UNFLAG,
+        json.encodeToString(
+            QuarantineUnflagPayload.serializer(),
+            QuarantineUnflagPayload(trackId),
         ),
     )
 
     suspend fun enqueuePlaylistAppend(
         playlistId: String,
         trackIds: List<String>,
-    ): Long = dao.insert(
-        CachedMutationEntity(
-            kind = MutationKind.PLAYLIST_APPEND,
-            payload = json.encodeToString(
-                PlaylistAppendPayload.serializer(),
-                PlaylistAppendPayload(playlistId, trackIds),
-            ),
+    ): Long = insertUserDriven(
+        MutationKind.PLAYLIST_APPEND,
+        json.encodeToString(
+            PlaylistAppendPayload.serializer(),
+            PlaylistAppendPayload(playlistId, trackIds),
         ),
     )
 
@@ -118,13 +144,19 @@ class MutationQueue @Inject constructor(
         trackId: String,
         reason: String,
         notes: String,
-    ): Long = dao.insert(
-        CachedMutationEntity(
-            kind = MutationKind.QUARANTINE_FLAG,
-            payload = json.encodeToString(
-                QuarantineFlagPayload.serializer(),
-                QuarantineFlagPayload(trackId, reason, notes),
-            ),
+    ): Long = insertUserDriven(
+        MutationKind.QUARANTINE_FLAG,
+        json.encodeToString(
+            QuarantineFlagPayload.serializer(),
+            QuarantineFlagPayload(trackId, reason, notes),
+        ),
+    )
+
+    suspend fun enqueueRequestCancel(requestId: String): Long = insertUserDriven(
+        MutationKind.REQUEST_CANCEL,
+        json.encodeToString(
+            RequestCancelPayload.serializer(),
+            RequestCancelPayload(requestId),
         ),
     )
 
@@ -135,15 +167,29 @@ class MutationQueue @Inject constructor(
         ),
     )
 
-    suspend fun enqueueRequestCancel(requestId: String): Long = dao.insert(
+    suspend fun enqueuePlaybackErrorReport(payload: PlaybackErrorReportPayload): Long = dao.insert(
         CachedMutationEntity(
-            kind = MutationKind.REQUEST_CANCEL,
-            payload = json.encodeToString(
-                RequestCancelPayload.serializer(),
-                RequestCancelPayload(requestId),
-            ),
+            kind = MutationKind.PLAYBACK_ERROR_REPORT,
+            payload = json.encodeToString(PlaybackErrorReportPayload.serializer(), payload),
         ),
     )
+
+    /**
+     * Durable close-by-id for an already-open server play row. Background
+     * path only (no user hint) — same as [enqueuePlayOffline].
+     */
+    suspend fun enqueuePlayEnded(payload: PlayEndedPayload): Long = dao.insert(
+        CachedMutationEntity(
+            kind = MutationKind.PLAY_ENDED,
+            payload = json.encodeToString(PlayEndedPayload.serializer(), payload),
+        ),
+    )
+
+    private suspend fun insertUserDriven(kind: String, payload: String): Long {
+        val id = dao.insert(CachedMutationEntity(kind = kind, payload = payload))
+        _userEnqueueHints.tryEmit(QUEUED_MESSAGE)
+        return id
+    }
 }
 
 /**
@@ -195,6 +241,19 @@ data class PlayOfflinePayload(
     val source: String? = null,
 )
 
+/**
+ * Persisted payload for `MutationKind.PLAY_ENDED`. The replayer re-fires
+ * `POST /api/events` with type=play_ended, closing the already-open server
+ * row [playEventId] at [durationPlayedMs]. Server-side close-by-id is
+ * idempotent (re-ending updates the same row and skips a duplicate
+ * skip_events insert), so a lost-response retry can't duplicate history.
+ */
+@Serializable
+data class PlayEndedPayload(
+    val playEventId: String,
+    val durationPlayedMs: Long,
+)
+
 /**
  * Persisted payload for `MutationKind.REQUEST_CANCEL` — the
  * `POST /api/requests/{id}/cancel` call lost during a connectivity
@@ -203,3 +262,20 @@ data class PlayOfflinePayload(
  */
 @Serializable
 data class RequestCancelPayload(val requestId: String)
+
+/**
+ * Persisted payload for `MutationKind.PLAYBACK_ERROR_REPORT` — the
+ * `POST /api/playback-errors` call lost during a connectivity hiccup.
+ * The replayer re-fires the POST with this body. Server is naturally
+ * idempotent enough — multiple reports of the same (track, user,
+ * kind) become multiple rows in the admin inbox, which is acceptable
+ * (the admin can resolve them all with one action). `clientId` is
+ * the existing playback client identifier from AuthStore.
+ */
+@Serializable
+data class PlaybackErrorReportPayload(
+    val trackId: String,
+    val kind: String,
+    val detail: String? = null,
+    val clientId: String,
+)

android/app/src/main/java/com/fabledsword/minstrel/cache/mutations/MutationReplayer.kt

@@ -1,3 +1,5 @@
+@file:Suppress("TooManyFunctions") // one dispatcher per mutation kind + replay helpers
+
 package com.fabledsword.minstrel.cache.mutations
 
 import com.fabledsword.minstrel.api.endpoints.AppendTracksRequest
@@ -5,9 +7,14 @@ import com.fabledsword.minstrel.api.endpoints.DiscoverApi
 import com.fabledsword.minstrel.api.endpoints.EventsApi
 import com.fabledsword.minstrel.api.endpoints.FlagRequest
 import com.fabledsword.minstrel.api.endpoints.LikesApi
+import com.fabledsword.minstrel.api.endpoints.PlaybackErrorReportRequest
+import com.fabledsword.minstrel.api.endpoints.PlaybackErrorsApi
 import com.fabledsword.minstrel.api.endpoints.PlaylistsApi
 import com.fabledsword.minstrel.api.endpoints.QuarantineApi
 import com.fabledsword.minstrel.api.endpoints.RequestsApi
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
+import com.fabledsword.minstrel.connectivity.ServerHealth
+import com.fabledsword.minstrel.models.wire.PlayEndedRequest
 import com.fabledsword.minstrel.models.wire.PlayOfflineRequest
 import com.fabledsword.minstrel.auth.AuthStore
 import com.fabledsword.minstrel.cache.db.dao.CachedMutationDao
@@ -17,12 +24,16 @@ import com.fabledsword.minstrel.likes.data.LikesRepository
 import com.fabledsword.minstrel.models.wire.CreateRequestBody
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
 import kotlinx.datetime.Clock
+import kotlinx.serialization.SerializationException
 import kotlinx.serialization.json.Json
+import retrofit2.HttpException
 import retrofit2.Retrofit
 import retrofit2.create
 import javax.inject.Inject
@@ -32,25 +43,24 @@ import javax.inject.Singleton
  * Drains the offline MutationQueue. Reads pending rows in FIFO order,
  * re-fires each call against the raw Retrofit API (NOT the high-level
  * Repository, which would re-enqueue on failure → infinite loop), and
- * deletes the row on 2xx success.
+ * resolves each to an [Outcome]:
+ *  - SENT  — server accepted (2xx) → delete the row.
+ *  - DROP  — permanently un-sendable (4xx, unknown kind/variant, corrupt
+ *            payload) → delete the row so it can't wedge the queue forever.
+ *  - RETRY — transient (transport, 5xx, 408, 429) → leave queued, bump
+ *            attempts, retry on the next trigger.
  *
  * Triggered by:
- *   - app start (MinstrelApplication @Inject forces the singleton's
- *     init block to subscribe)
- *   - every time AuthStore.sessionCookie transitions to a non-null
- *     value (sign-in, app launch with persisted cookie)
+ *   - app start (MinstrelApplication @Inject forces the singleton's init)
+ *   - AuthStore.sessionCookie transitioning to non-null (sign-in / cold
+ *     start with a persisted cookie)
+ *   - NetworkStatusController recovering to Healthy (server reachable again
+ *     mid-session — covers offline→online without needing a cold start)
  *
- * Single in-flight via the `mutex` — back-to-back triggers collapse
- * into one drain pass. A proper connectivity-listener / WorkManager
- * job that re-tries on Wi-Fi-came-back is a follow-up; for MVP the
- * sign-in + app-open triggers cover the common offline → online
- * transition (operator unlocks phone, opens app).
- *
- * Failed rows stay in the queue with their `attempts` and
- * `lastAttemptAt` updated. They get another chance on the next
- * trigger; no exponential backoff or max-attempts yet — the rows are
- * small (low single-digit count for typical use) so retry-forever is
- * cheap.
+ * Single in-flight via the [mutex]; back-to-back triggers collapse into one
+ * drain pass. No exponential backoff / max-attempts: the rows are few for
+ * typical use, and permanent failures are now dropped rather than retried
+ * forever.
  */
 @Singleton
 class MutationReplayer @Inject constructor(
@@ -58,6 +68,7 @@ class MutationReplayer @Inject constructor(
     private val authStore: AuthStore,
     private val json: Json,
     @ApplicationScope private val scope: CoroutineScope,
+    networkStatus: NetworkStatusController,
     retrofit: Retrofit,
 ) {
     private val likesApi: LikesApi = retrofit.create()
@@ -66,9 +77,12 @@ class MutationReplayer @Inject constructor(
     private val playlistsApi: PlaylistsApi = retrofit.create()
     private val eventsApi: EventsApi = retrofit.create()
     private val requestsApi: RequestsApi = retrofit.create()
+    private val playbackErrorsApi: PlaybackErrorsApi = retrofit.create()
 
     private val mutex = Mutex()
 
+    private enum class Outcome { SENT, DROP, RETRY }
+
     init {
         scope.launch {
             authStore.sessionCookie
@@ -76,6 +90,16 @@ class MutationReplayer @Inject constructor(
                 .distinctUntilChanged()
                 .collect { drainSafe() }
         }
+        // Server-reachable-again: replay queued writes the moment the
+        // health signal recovers, so an offline→online transition mid-
+        // session doesn't wait for the next cold start / re-auth.
+        scope.launch {
+            networkStatus.state
+                .map { it == ServerHealth.Healthy }
+                .distinctUntilChanged()
+                .filter { it }
+                .collect { drainSafe() }
+        }
     }
 
     /** Public entry-point; coalesces concurrent triggers via a Mutex. */
@@ -90,172 +114,185 @@ class MutationReplayer @Inject constructor(
 
     private suspend fun drain() {
         val rows = dao.getAll()
+        // Collapse superseded like-toggles: only the latest desired state per
+        // (entity) is replayed; older toggles for the same entity are dropped
+        // unsent. Without this, partial-failure + differential retry could
+        // replay an older toggle last and invert the final like state.
+        val superseded = supersededLikeToggleIds(rows)
         for (row in rows) {
-            val sent = runCatching { dispatch(row) }.getOrDefault(false)
-            if (sent) {
+            if (row.id in superseded) {
                 dao.delete(row.id)
-            } else {
-                dao.recordAttempt(row.id, Clock.System.now())
+                continue
+            }
+            when (outcomeFor(row)) {
+                Outcome.SENT, Outcome.DROP -> dao.delete(row.id)
+                Outcome.RETRY -> dao.recordAttempt(row.id, Clock.System.now())
             }
         }
     }
 
+    /** Row ids of like-toggles superseded by a later toggle for the same entity. */
+    private fun supersededLikeToggleIds(rows: List<CachedMutationEntity>): Set<Long> {
+        val latestByEntity = HashMap<String, Long>()
+        val superseded = HashSet<Long>()
+        rows.asSequence()
+            .filter { it.kind == MutationKind.LIKE_TOGGLE }
+            .forEach { row ->
+                val decoded = runCatching {
+                    json.decodeFromString(LikeTogglePayload.serializer(), row.payload)
+                }.getOrNull()
+                if (decoded != null) {
+                    val key = "${decoded.entityType}:${decoded.entityId}"
+                    // `rows` is ascending by id, so a prior entry is always older.
+                    latestByEntity.put(key, row.id)?.let(superseded::add)
+                }
+            }
+        return superseded
+    }
+
+    private suspend fun outcomeFor(row: CachedMutationEntity): Outcome = try {
+        dispatch(row)
+    } catch (e: HttpException) {
+        if (isPermanent(e.code())) Outcome.DROP else Outcome.RETRY
+    } catch (@Suppress("SwallowedException") e: SerializationException) {
+        // Corrupt / schema-incompatible payload — permanent, drop it.
+        Outcome.DROP
+    } catch (@Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable) {
+        // Transport / unknown — leave queued for the next pass.
+        Outcome.RETRY
+    }
+
+    /** 4xx are permanent except the two "retry me" statuses. */
+    private fun isPermanent(code: Int): Boolean =
+        code in HTTP_CLIENT_ERR_MIN..HTTP_CLIENT_ERR_MAX &&
+            code != HTTP_TIMEOUT && code != HTTP_TOO_MANY
+
     /**
-     * Returns true if the server accepted the call, false on any
-     * failure (transport, server error, decode). The replayer treats
-     * false as "leave the row for next pass" — it doesn't try to
-     * distinguish permanent rejections from transient ones; a row
-     * that consistently fails will accumulate attempt count and
-     * lastAttemptAt for diagnostics.
+     * Returns the outcome of replaying one row. SENT on a 2xx; DROP for an
+     * unknown kind/variant. Network / HTTP failures THROW and are classified
+     * by [outcomeFor] — dispatchers no longer swallow.
      */
-    private suspend fun dispatch(row: CachedMutationEntity): Boolean = when (row.kind) {
+    private suspend fun dispatch(row: CachedMutationEntity): Outcome = when (row.kind) {
         MutationKind.LIKE_TOGGLE -> dispatchLikeToggle(row.payload)
         MutationKind.REQUEST_CREATE -> dispatchRequestCreate(row.payload)
         MutationKind.QUARANTINE_UNFLAG -> dispatchQuarantineUnflag(row.payload)
         MutationKind.PLAYLIST_APPEND -> dispatchPlaylistAppend(row.payload)
         MutationKind.QUARANTINE_FLAG -> dispatchQuarantineFlag(row.payload)
         MutationKind.PLAY_OFFLINE -> dispatchPlayOffline(row.payload)
+        MutationKind.PLAY_ENDED -> dispatchPlayEnded(row.payload)
         MutationKind.REQUEST_CANCEL -> dispatchRequestCancel(row.payload)
-        else -> {
-            // Unknown kind — drop the row by claiming success so a
-            // stale schema entry can't wedge the queue forever.
-            true
-        }
+        MutationKind.PLAYBACK_ERROR_REPORT -> dispatchPlaybackErrorReport(row.payload)
+        // Unknown kind — drop so a stale schema entry can't wedge the queue.
+        else -> Outcome.DROP
     }
 
-    private suspend fun dispatchLikeToggle(payload: String): Boolean {
+    private suspend fun dispatchLikeToggle(payload: String): Outcome {
         val decoded = json.decodeFromString(LikeTogglePayload.serializer(), payload)
         val kindPath = when (decoded.entityType) {
             LikesRepository.ENTITY_ARTIST -> "artists"
             LikesRepository.ENTITY_ALBUM -> "albums"
             LikesRepository.ENTITY_TRACK -> "tracks"
-            else -> return true  // unknown variant — drop.
+            else -> return Outcome.DROP
         }
-        return try {
-            if (decoded.desiredState) {
-                likesApi.like(kindPath, decoded.entityId)
-            } else {
-                likesApi.unlike(kindPath, decoded.entityId)
-            }
-            true
-        } catch (
-            @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
-        ) {
-            // Intentional swallow: the row stays in the queue with
-            // attempts + lastAttemptAt incremented; next drain pass
-            // retries. Per-attempt diagnostic logging lands when we
-            // wire up Timber at the replayer level.
-            false
+        if (decoded.desiredState) {
+            likesApi.like(kindPath, decoded.entityId)
+        } else {
+            likesApi.unlike(kindPath, decoded.entityId)
         }
+        return Outcome.SENT
     }
 
-    private suspend fun dispatchRequestCreate(payload: String): Boolean {
+    private suspend fun dispatchRequestCreate(payload: String): Outcome {
         val decoded = json.decodeFromString(RequestCreatePayload.serializer(), payload)
-        val body = CreateRequestBody(
-            kind = decoded.kind,
-            artistMbid = decoded.artistMbid,
-            artistName = decoded.artistName,
-            albumMbid = decoded.albumMbid,
-            albumTitle = decoded.albumTitle,
-            trackMbid = decoded.trackMbid,
-            trackTitle = decoded.trackTitle,
+        discoverApi.createRequest(
+            CreateRequestBody(
+                kind = decoded.kind,
+                artistMbid = decoded.artistMbid,
+                artistName = decoded.artistName,
+                albumMbid = decoded.albumMbid,
+                albumTitle = decoded.albumTitle,
+                trackMbid = decoded.trackMbid,
+                trackTitle = decoded.trackTitle,
+            ),
         )
-        return try {
-            discoverApi.createRequest(body)
-            true
-        } catch (
-            @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
-        ) {
-            // Intentional swallow: the row stays in the queue with
-            // attempts + lastAttemptAt incremented; next drain pass
-            // retries. Per-attempt diagnostic logging lands when we
-            // wire up Timber at the replayer level.
-            false
-        }
+        return Outcome.SENT
     }
 
-    private suspend fun dispatchQuarantineUnflag(payload: String): Boolean {
+    private suspend fun dispatchQuarantineUnflag(payload: String): Outcome {
         val decoded = json.decodeFromString(QuarantineUnflagPayload.serializer(), payload)
-        return try {
-            quarantineApi.unflag(decoded.trackId)
-            true
-        } catch (
-            @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
-        ) {
-            // Intentional swallow: the row stays in the queue with
-            // attempts + lastAttemptAt incremented; next drain pass
-            // retries. Per-attempt diagnostic logging lands when we
-            // wire up Timber at the replayer level.
-            false
-        }
+        quarantineApi.unflag(decoded.trackId)
+        return Outcome.SENT
     }
 
-    private suspend fun dispatchPlaylistAppend(payload: String): Boolean {
+    private suspend fun dispatchPlaylistAppend(payload: String): Outcome {
         val decoded = json.decodeFromString(PlaylistAppendPayload.serializer(), payload)
-        return try {
-            playlistsApi.appendTracks(
-                playlistId = decoded.playlistId,
-                body = AppendTracksRequest(trackIds = decoded.trackIds),
-            )
-            true
-        } catch (
-            @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
-        ) {
-            // Intentional swallow: row stays queued; next drain pass retries.
-            false
-        }
+        playlistsApi.appendTracks(
+            playlistId = decoded.playlistId,
+            body = AppendTracksRequest(trackIds = decoded.trackIds),
+        )
+        return Outcome.SENT
     }
 
-    private suspend fun dispatchQuarantineFlag(payload: String): Boolean {
+    private suspend fun dispatchQuarantineFlag(payload: String): Outcome {
         val decoded = json.decodeFromString(QuarantineFlagPayload.serializer(), payload)
-        return try {
-            quarantineApi.flag(
-                FlagRequest(
-                    trackId = decoded.trackId,
-                    reason = decoded.reason,
-                    notes = decoded.notes,
-                ),
-            )
-            true
-        } catch (
-            @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
-        ) {
-            // Intentional swallow: row stays queued; next drain pass retries.
-            false
-        }
+        quarantineApi.flag(
+            FlagRequest(
+                trackId = decoded.trackId,
+                reason = decoded.reason,
+                notes = decoded.notes,
+            ),
+        )
+        return Outcome.SENT
     }
 
-    private suspend fun dispatchPlayOffline(payload: String): Boolean {
+    private suspend fun dispatchPlayOffline(payload: String): Outcome {
         val decoded = json.decodeFromString(PlayOfflinePayload.serializer(), payload)
-        return try {
-            eventsApi.playOffline(
-                PlayOfflineRequest(
-                    trackId = decoded.trackId,
-                    clientId = decoded.clientId,
-                    at = decoded.atIso,
-                    durationPlayedMs = decoded.durationPlayedMs,
-                    source = decoded.source,
-                ),
-            )
-            true
-        } catch (
-            @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
-        ) {
-            // Intentional swallow: row stays queued; next drain pass retries.
-            false
-        }
+        eventsApi.playOffline(
+            PlayOfflineRequest(
+                trackId = decoded.trackId,
+                clientId = decoded.clientId,
+                at = decoded.atIso,
+                durationPlayedMs = decoded.durationPlayedMs,
+                source = decoded.source,
+            ),
+        )
+        return Outcome.SENT
     }
 
-    private suspend fun dispatchRequestCancel(payload: String): Boolean {
+    private suspend fun dispatchPlayEnded(payload: String): Outcome {
+        val decoded = json.decodeFromString(PlayEndedPayload.serializer(), payload)
+        eventsApi.playEnded(
+            PlayEndedRequest(
+                playEventId = decoded.playEventId,
+                durationPlayedMs = decoded.durationPlayedMs,
+            ),
+        )
+        return Outcome.SENT
+    }
+
+    private suspend fun dispatchRequestCancel(payload: String): Outcome {
         val decoded = json.decodeFromString(RequestCancelPayload.serializer(), payload)
-        return try {
-            requestsApi.cancel(decoded.requestId)
-            true
-        } catch (
-            @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
-        ) {
-            // Intentional swallow: row stays queued; next drain pass retries.
-            false
-        }
+        requestsApi.cancel(decoded.requestId)
+        return Outcome.SENT
+    }
+
+    private suspend fun dispatchPlaybackErrorReport(payload: String): Outcome {
+        val decoded = json.decodeFromString(PlaybackErrorReportPayload.serializer(), payload)
+        playbackErrorsApi.report(
+            PlaybackErrorReportRequest(
+                trackId = decoded.trackId,
+                kind = decoded.kind,
+                detail = decoded.detail,
+                clientId = decoded.clientId,
+            ),
+        )
+        return Outcome.SENT
+    }
+
+    private companion object {
+        const val HTTP_CLIENT_ERR_MIN = 400
+        const val HTTP_CLIENT_ERR_MAX = 499
+        const val HTTP_TIMEOUT = 408
+        const val HTTP_TOO_MANY = 429
     }
 }

android/app/src/main/java/com/fabledsword/minstrel/cache/mutations/OfflineWriteHintViewModel.kt

@@ -0,0 +1,20 @@
+package com.fabledsword.minstrel.cache.mutations
+
+import androidx.lifecycle.ViewModel
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.Flow
+import javax.inject.Inject
+
+/**
+ * Hilt-injectable wrapper exposing [MutationQueue.userEnqueueHints] to
+ * ShellScaffold. The queue itself is an app-scoped singleton; this VM
+ * just bridges its SharedFlow into a `hiltViewModel()`-resolvable
+ * surface so ShellScaffold can collect it without an EntryPoint
+ * accessor. Mirrors PlaybackErrorViewModel.
+ */
+@HiltViewModel
+class OfflineWriteHintViewModel @Inject constructor(
+    mutationQueue: MutationQueue,
+) : ViewModel() {
+    val messages: Flow<String> = mutationQueue.userEnqueueHints
+}

android/app/src/main/java/com/fabledsword/minstrel/cache/sync/SyncController.kt

@@ -2,6 +2,8 @@ package com.fabledsword.minstrel.cache.sync
 
 import com.fabledsword.minstrel.api.endpoints.SyncApi
 import com.fabledsword.minstrel.auth.AuthStore
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
+import com.fabledsword.minstrel.connectivity.ServerHealth
 import com.fabledsword.minstrel.cache.db.dao.CachedAlbumDao
 import com.fabledsword.minstrel.cache.db.dao.CachedArtistDao
 import com.fabledsword.minstrel.cache.db.dao.CachedTrackDao
@@ -16,8 +18,11 @@ import com.fabledsword.minstrel.models.wire.SyncArtistWire
 import com.fabledsword.minstrel.models.wire.SyncTrackWire
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.sync.Mutex
 import kotlinx.datetime.Clock
 import retrofit2.Retrofit
 import retrofit2.create
@@ -50,10 +55,15 @@ class SyncController @Inject constructor(
     private val trackDao: CachedTrackDao,
     private val authStore: AuthStore,
     @ApplicationScope private val scope: CoroutineScope,
+    networkStatus: NetworkStatusController,
     retrofit: Retrofit,
 ) {
     private val api: SyncApi = retrofit.create()
 
+    // Single in-flight guard: the cookie + health-recovery triggers (and a
+    // pull-to-refresh) can fire concurrently; coalesce them into one pass.
+    private val mutex = Mutex()
+
     init {
         scope.launch {
             authStore.sessionCookie
@@ -61,11 +71,25 @@ class SyncController @Inject constructor(
                 .distinctUntilChanged()
                 .collect { syncSafe() }
         }
+        // Re-sync when the server becomes reachable again mid-session, so a
+        // delta missed while offline lands without waiting for a cold start.
+        scope.launch {
+            networkStatus.state
+                .map { it == ServerHealth.Healthy }
+                .distinctUntilChanged()
+                .filter { it }
+                .collect { syncSafe() }
+        }
     }
 
     /** Public entry-point for "Sync now" affordances. Swallows errors. */
     suspend fun syncSafe() {
-        runCatching { sync() }
+        if (!mutex.tryLock()) return
+        try {
+            runCatching { sync() }
+        } finally {
+            mutex.unlock()
+        }
     }
 
     private suspend fun sync() {

android/app/src/main/java/com/fabledsword/minstrel/connectivity/ConnectivityObserver.kt

@@ -14,11 +14,23 @@ import javax.inject.Inject
 import javax.inject.Singleton
 
 /**
- * Single source of truth for the device's "is the internet usable
- * right now" signal — wraps [ConnectivityManager] and exposes a hot
- * cold-startable Flow that emits `false` while the active network
- * lacks INTERNET + VALIDATED capabilities (airplane mode, no carrier,
- * captive portal, etc.) and `true` once a usable network appears.
+ * Single source of truth for "does the device have a network link at
+ * all" — wraps [ConnectivityManager] and exposes a hot cold-startable
+ * Flow that emits `false` only when there is no active INTERNET-capable
+ * network (airplane mode, no carrier/Wi-Fi) and `true` once any network
+ * link appears.
+ *
+ * Deliberately does NOT require `NET_CAPABILITY_VALIDATED`. VALIDATED
+ * tracks whether Android reached its own WAN internet-validation probe
+ * (Google's `generate_204`) — which is the wrong question for a
+ * self-hosted server that is usually on the LAN. A transient WAN/DNS
+ * blip (or Android's periodic re-validation) momentarily drops VALIDATED
+ * while the Minstrel box stays perfectly reachable; gating on it flipped
+ * the app to Offline with no debounce and fast-failed in-flight playback
+ * via [com.fabledsword.minstrel.player.OfflineGatedDataSource]. The
+ * authority on whether *Minstrel* is reachable is the `/healthz` poll
+ * ([com.fabledsword.minstrel.connectivity.NetworkStatusController], which
+ * has its own failure hysteresis), not this coarse device-link signal.
  *
  * Used by the shell-level ConnectionErrorBanner; downstream
  * repositories can also collect this to gate retry loops.
@@ -35,36 +47,36 @@ class ConnectivityObserver @Inject constructor(
             .build()
         val callback = object : ConnectivityManager.NetworkCallback() {
             override fun onAvailable(network: Network) {
-                trySend(hasUsableInternet())
+                trySend(hasActiveNetwork())
             }
             override fun onLost(network: Network) {
-                trySend(hasUsableInternet())
+                trySend(hasActiveNetwork())
             }
             override fun onCapabilitiesChanged(
                 network: Network,
                 capabilities: NetworkCapabilities,
             ) {
+                // INTERNET only -- NOT VALIDATED. A WAN/validation flicker
+                // must not read as "device offline" when the LAN (and the
+                // Minstrel server on it) is still reachable. /healthz is the
+                // authority on server reachability.
                 trySend(
                     capabilities.hasCapability(
                         NetworkCapabilities.NET_CAPABILITY_INTERNET,
-                    ) &&
-                        capabilities.hasCapability(
-                            NetworkCapabilities.NET_CAPABILITY_VALIDATED,
-                        ),
+                    ),
                 )
             }
         }
         cm.registerNetworkCallback(request, callback)
         // Seed the initial value so the banner doesn't flash before the
         // first capability callback fires.
-        trySend(hasUsableInternet())
+        trySend(hasActiveNetwork())
         awaitClose { cm.unregisterNetworkCallback(callback) }
     }.distinctUntilChanged()
 
-    private fun hasUsableInternet(): Boolean {
+    private fun hasActiveNetwork(): Boolean {
         val caps = cm.activeNetwork?.let { cm.getNetworkCapabilities(it) }
         return caps != null &&
-            caps.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET) &&
-            caps.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)
+            caps.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
     }
 }

android/app/src/main/java/com/fabledsword/minstrel/connectivity/NetworkStatusController.kt

@@ -0,0 +1,176 @@
+package com.fabledsword.minstrel.connectivity
+
+import androidx.compose.runtime.staticCompositionLocalOf
+import com.fabledsword.minstrel.BuildConfig
+import com.fabledsword.minstrel.auth.AuthStore
+import com.fabledsword.minstrel.di.ApplicationScope
+import com.fabledsword.minstrel.update.api.HealthzApi
+import com.fabledsword.minstrel.update.api.HealthzResponse
+import com.fabledsword.minstrel.update.data.VersionResult
+import com.fabledsword.minstrel.update.data.isVersionNewer
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import retrofit2.Retrofit
+import timber.log.Timber
+import java.util.concurrent.atomic.AtomicLong
+import javax.inject.Inject
+import javax.inject.Singleton
+
+private const val POLL_HEALTHY_MS = 5 * 60 * 1000L
+private const val POLL_DEGRADED_MS = 20_000L
+private const val ARBITRATE_MIN_GAP_MS = 2_000L
+
+/**
+ * THE single authority on network/server reachability. Absorbs the former
+ * VersionCheckController (the /healthz poll + version parsing) and
+ * ServerHealthController (the tri-state derive) into one signal-driven unit so
+ * the app has one place that answers "can we reach Minstrel?" — not three
+ * half-systems reporting differently.
+ *
+ * Inputs (all funnel through a single-consumer intent channel for thread
+ * safety — [reportSuccess]/[reportFailure] are called from the audio read path
+ * and OkHttp threads):
+ *  - device link transitions ([ConnectivityObserver]); link-return triggers an
+ *    immediate probe so recovery is near-instant (fixes the sticky banner).
+ *  - periodic /healthz probe, adaptive cadence (calm when Healthy, fast when down).
+ *  - reportSuccess / reportFailure from the API interceptor, the audio data
+ *    source, and the playback-error reporter.
+ *  - recheck() from pull-to-refresh and the banner.
+ *
+ * Version compatibility is a byproduct of the same /healthz response.
+ *
+ * Constructed at launch via the construct-the-singleton trick in
+ * [com.fabledsword.minstrel.MinstrelApplication].
+ */
+@Singleton
+class NetworkStatusController @Inject constructor(
+    @ApplicationScope private val scope: CoroutineScope,
+    connectivity: ConnectivityObserver,
+    private val authStore: AuthStore,
+    retrofit: Retrofit,
+) {
+    private val api: HealthzApi = retrofit.create(HealthzApi::class.java)
+    private val machine = ReachabilityMachine()
+    private val lastProbeAtMs = AtomicLong(0)
+
+    private val stateInternal = MutableStateFlow(ServerHealth.Healthy)
+    val state: StateFlow<ServerHealth> = stateInternal.asStateFlow()
+
+    private val versionInternal = MutableStateFlow(VersionResult.SKIPPED)
+    val versionResult: StateFlow<VersionResult> = versionInternal.asStateFlow()
+
+    private sealed interface Intent {
+        data class Link(val up: Boolean) : Intent
+        data class Probe(val resp: HealthzResponse?) : Intent
+        object OpSuccess : Intent
+        object OpFailure : Intent
+    }
+
+    private val intents = Channel<Intent>(Channel.UNLIMITED)
+
+    init {
+        scope.launch { reduceLoop() }
+        scope.launch {
+            connectivity.online.collect { up ->
+                intents.trySend(Intent.Link(up))
+                if (up) probeOnce()
+            }
+        }
+        scope.launch { pollLoop() }
+    }
+
+    /** A real server op verifiably succeeded — self-proving recovery. Cheap; safe on hot paths. */
+    fun reportSuccess() {
+        if (stateInternal.value != ServerHealth.Healthy) intents.trySend(Intent.OpSuccess)
+    }
+
+    /** A real network op failed — triggers /healthz arbitration. No-op when already Offline. */
+    fun reportFailure() {
+        if (stateInternal.value == ServerHealth.Offline) return
+        intents.trySend(Intent.OpFailure)
+    }
+
+    /** One-shot recheck for pull-to-refresh and the banner. */
+    fun recheck() {
+        scope.launch { probeOnce(force = true) }
+    }
+
+    private suspend fun reduceLoop() {
+        for (intent in intents) {
+            val now = System.currentTimeMillis()
+            when (intent) {
+                is Intent.Link -> machine.onLinkChange(intent.up)
+                is Intent.Probe -> applyProbe(intent.resp, now)
+                Intent.OpSuccess -> machine.onSuccess()
+                Intent.OpFailure -> {
+                    machine.onOpFailure(now)
+                    // Arbitrate off the reducer thread: awaiting a stalled
+                    // /healthz here would block a concurrent self-proving
+                    // success from snapping us straight back to Healthy.
+                    scope.launch { probeOnce() }
+                }
+            }
+            emit(machine.health())
+        }
+    }
+
+    private fun applyProbe(resp: HealthzResponse?, now: Long) {
+        if (resp == null) {
+            machine.onProbeFailure(now)
+        } else {
+            machine.onSuccess()
+            versionInternal.value = versionResultFor(resp)
+        }
+    }
+
+    private fun emit(next: ServerHealth) {
+        if (stateInternal.value != next) {
+            Timber.w("NetworkStatus -> %s", next)
+            stateInternal.value = next
+        }
+    }
+
+    private suspend fun pollLoop() {
+        probeOnce()
+        while (true) {
+            val interval =
+                if (stateInternal.value == ServerHealth.Healthy) POLL_HEALTHY_MS
+                else POLL_DEGRADED_MS
+            delay(interval)
+            probeOnce()
+        }
+    }
+
+    private suspend fun probeOnce(force: Boolean = false) {
+        // Startup guard: don't poll the localhost placeholder before AuthStore
+        // hydrates the real base URL — that false failure used to flash the banner.
+        if (authStore.baseUrl.value == AuthStore.DEFAULT_BASE_URL) return
+        val now = System.currentTimeMillis()
+        if (!force && now - lastProbeAtMs.get() < ARBITRATE_MIN_GAP_MS) return
+        lastProbeAtMs.set(now)
+        val resp = runCatching { api.check() }.getOrNull()
+        intents.trySend(Intent.Probe(resp))
+    }
+
+    private fun versionResultFor(resp: HealthzResponse): VersionResult {
+        val min = resp.minClientVersion
+        return when {
+            min.isEmpty() -> VersionResult.SKIPPED
+            isVersionNewer(min, BuildConfig.VERSION_NAME) -> VersionResult.TOO_OLD
+            else -> VersionResult.OK
+        }
+    }
+}
+
+/**
+ * Reactive [ServerHealth] snapshot provided once at the app root. Lets leaf
+ * composables (TrackRow gating, write-affordance disabling) branch on health
+ * without re-injecting the controller. Defaults to Healthy so previews/tests
+ * don't crash.
+ */
+val LocalServerHealth = staticCompositionLocalOf { ServerHealth.Healthy }

android/app/src/main/java/com/fabledsword/minstrel/connectivity/ReachabilityMachine.kt

@@ -0,0 +1,88 @@
+package com.fabledsword.minstrel.connectivity
+
+internal const val ESCALATE_AFTER_MS = 120_000L
+internal const val CORROBORATION_WINDOW_MS = 30_000L
+internal const val CORROBORATION_OP_THRESHOLD = 2
+
+/**
+ * Pure reachability state machine. No Android, no coroutines, no real clock —
+ * every entry point takes `nowMs`, so it is fully deterministic and unit-
+ * testable. [NetworkStatusController] wires real time + signals around it.
+ *
+ * Reachability (independent of the device link):
+ *  - Reachable   last evidence says the server answered.
+ *  - Unstable    a probe failed; arbitration/escalation pending.
+ *  - Unreachable corroborated or sustained failure.
+ *
+ * [health] folds the device link over that: no link → Offline; otherwise the
+ * reachability maps Reachable→Healthy, Unstable→Unstable, Unreachable→ServerDown.
+ *
+ * Principle: **success is self-proving, failure is ambiguous.** [onSuccess]
+ * (a real server byte-read or API 2xx, or a successful /healthz) snaps straight
+ * back to Reachable. A failure only escalates when a /healthz probe corroborates
+ * it ([onProbeFailure]) — either via fresh op-failure corroboration or the
+ * sustained-time backstop.
+ */
+class ReachabilityMachine {
+
+    private enum class Reachability { Reachable, Unstable, Unreachable }
+
+    private var linkUp = true
+    private var reachability = Reachability.Reachable
+    private var failureStreakStartMs: Long? = null
+    private val recentOpFailures = ArrayDeque<Long>()
+
+    fun onLinkChange(up: Boolean) {
+        linkUp = up
+        // Link transitions don't reset reachability — a restored link keeps the
+        // last-known server reachability until a fresh probe/op result arrives.
+        if (!up) recentOpFailures.clear()
+    }
+
+    /** A real successful server op (stream read, API 2xx) or a successful /healthz. */
+    fun onSuccess() {
+        reachability = Reachability.Reachable
+        failureStreakStartMs = null
+        recentOpFailures.clear()
+    }
+
+    /** A real network op failed. Ambiguous on its own — records corroboration. */
+    fun onOpFailure(nowMs: Long) {
+        pruneOpFailures(nowMs)
+        recentOpFailures.addLast(nowMs)
+    }
+
+    /** A /healthz probe failed — the arbiter. Escalates per corroboration/backstop. */
+    fun onProbeFailure(nowMs: Long) {
+        pruneOpFailures(nowMs)
+        if (reachability == Reachability.Reachable) {
+            reachability = Reachability.Unstable
+            failureStreakStartMs = nowMs
+        }
+        if (reachability == Reachability.Unstable && shouldEscalate(nowMs)) {
+            reachability = Reachability.Unreachable
+        }
+    }
+
+    fun health(): ServerHealth = when {
+        !linkUp -> ServerHealth.Offline
+        reachability == Reachability.Reachable -> ServerHealth.Healthy
+        reachability == Reachability.Unstable -> ServerHealth.Unstable
+        else -> ServerHealth.ServerDown
+    }
+
+    private fun shouldEscalate(nowMs: Long): Boolean {
+        val corroborated = recentOpFailures.size >= CORROBORATION_OP_THRESHOLD
+        val sustained =
+            failureStreakStartMs?.let { nowMs - it >= ESCALATE_AFTER_MS } ?: false
+        return corroborated || sustained
+    }
+
+    private fun pruneOpFailures(nowMs: Long) {
+        while (recentOpFailures.isNotEmpty() &&
+            nowMs - recentOpFailures.first() > CORROBORATION_WINDOW_MS
+        ) {
+            recentOpFailures.removeFirst()
+        }
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/connectivity/ReachabilityReportingInterceptor.kt

@@ -0,0 +1,49 @@
+package com.fabledsword.minstrel.connectivity
+
+import com.fabledsword.minstrel.api.BaseUrlInterceptor.Companion.PLACEHOLDER_HOST
+import dagger.Lazy
+import okhttp3.Interceptor
+import okhttp3.Response
+import java.io.IOException
+import javax.inject.Inject
+import javax.inject.Singleton
+
+private const val HEALTHZ_PATH = "/healthz"
+
+/**
+ * Feeds real Minstrel API outcomes into [NetworkStatusController]. A 2xx is
+ * self-proving proof the server is reachable → reportSuccess(); a transport
+ * [IOException] (no response at all) → reportFailure(), which triggers /healthz
+ * arbitration.
+ *
+ * MUST run first in the OkHttp chain (before [BaseUrlInterceptor]) so the host
+ * is still the [PLACEHOLDER_HOST] sentinel: this shared client also fetches
+ * EXTERNAL artwork (musicbrainz / coverartarchive), and an external image
+ * loading must NOT be read as "our server is reachable" — only sentinel-host
+ * requests are Minstrel-bound. 5xx is deliberately NOT a failure (the server
+ * answered), and /healthz is skipped to avoid a feedback loop with the poll.
+ *
+ * [NetworkStatusController] is injected as a [Lazy] to break the Hilt cycle:
+ * the controller needs `Retrofit`, which needs `OkHttpClient`, which needs this
+ * interceptor. By the time a request flows through, the controller singleton is
+ * already constructed (construct-the-singleton trick in MinstrelApplication).
+ */
+@Singleton
+class ReachabilityReportingInterceptor @Inject constructor(
+    private val networkStatus: Lazy<NetworkStatusController>,
+) : Interceptor {
+    override fun intercept(chain: Interceptor.Chain): Response {
+        val request = chain.request()
+        val isMinstrel = request.url.host == PLACEHOLDER_HOST
+        val isHealthz = request.url.encodedPath.endsWith(HEALTHZ_PATH)
+        if (!isMinstrel || isHealthz) return chain.proceed(request)
+        return try {
+            val response = chain.proceed(request)
+            if (response.isSuccessful) networkStatus.get().reportSuccess()
+            response
+        } catch (e: IOException) {
+            networkStatus.get().reportFailure()
+            throw e
+        }
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/connectivity/ServerHealth.kt

@@ -0,0 +1,15 @@
+package com.fabledsword.minstrel.connectivity
+
+/**
+ * The single reachability signal every consumer branches on.
+ *
+ *  - [Healthy]    link up, /healthz ok — normal network behavior.
+ *  - [Unstable]   link up, a recent failure with arbitration pending —
+ *                 INFORMATIONAL ONLY. Does NOT gate playback; preserves the
+ *                 anti-flicker intent of commit 5c0db429 while still warning
+ *                 the user that something is flaky.
+ *  - [ServerDown] link up but /healthz failing, corroborated or sustained —
+ *                 gate to cache-only.
+ *  - [Offline]    no device link at all — gate to cache-only.
+ */
+enum class ServerHealth { Healthy, Unstable, ServerDown, Offline }

android/app/src/main/java/com/fabledsword/minstrel/connectivity/ui/ConnectionErrorBanner.kt

@@ -14,77 +14,121 @@ import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
-import androidx.lifecycle.viewModelScope
 import com.composables.icons.lucide.CloudOff
 import com.composables.icons.lucide.Lucide
-import com.fabledsword.minstrel.connectivity.ConnectivityObserver
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
+import com.fabledsword.minstrel.connectivity.ServerHealth
 import dagger.hilt.android.lifecycle.HiltViewModel
-import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.stateIn
 import javax.inject.Inject
 
-private const val ONLINE_SHARE_STOP_TIMEOUT_MS = 5_000L
+private const val BACK_ONLINE_FLASH_MS = 2_000L
 
 /**
- * Tiny VM that just lifts the [ConnectivityObserver] singleton's
- * Flow into a StateFlow with the standard sharing strategy. Keeps
- * the banner composable pure-presentation.
+ * Exposes [NetworkStatusController]'s tri-state directly to the banner. No
+ * re-wrapping StateFlow — the controller's is already app-scoped and warm.
  */
 @HiltViewModel
 class ConnectivityBannerViewModel @Inject constructor(
-    observer: ConnectivityObserver,
+    networkStatus: NetworkStatusController,
     @Suppress("UnusedPrivateProperty") savedStateHandle: SavedStateHandle,
 ) : ViewModel() {
-    val online: StateFlow<Boolean> = observer.online.stateIn(
-        scope = viewModelScope,
-        started = SharingStarted.WhileSubscribed(ONLINE_SHARE_STOP_TIMEOUT_MS),
-        initialValue = true,
-    )
+    val health: StateFlow<ServerHealth> = networkStatus.state
 }
 
 /**
- * Banner shown at the top of the shell when the device has no usable
- * internet. Mirrors Flutter's ConnectionErrorBanner: red-tinted error
- * surface, CloudOff icon, "No connection — check Wi-Fi or mobile
- * data" copy. Auto-hides via slide+fade when connectivity returns.
+ * Shell banner. Tells the user *why* they're degraded — no link vs server-down
+ * — plus a non-alarming "Reconnecting…" for the transient [ServerHealth.Unstable]
+ * window, and a brief "Back online" confirmation when health recovers so
+ * recovery is unmistakable. Sentence case, understated voice (design system).
  */
 @Composable
 fun ConnectionErrorBanner(
     viewModel: ConnectivityBannerViewModel = hiltViewModel(),
 ) {
-    val online by viewModel.online.collectAsStateWithLifecycle()
+    val health by viewModel.health.collectAsStateWithLifecycle()
+    var showBackOnline by remember { mutableStateOf(false) }
+    var wasDown by remember { mutableStateOf(false) }
+
+    LaunchedEffect(health) {
+        val down = health == ServerHealth.Offline || health == ServerHealth.ServerDown
+        if (health == ServerHealth.Healthy && wasDown) {
+            // try/finally so a mid-delay cancellation (health flips again) can't
+            // orphan the flag and leave "Back online" stuck on screen.
+            try {
+                showBackOnline = true
+                delay(BACK_ONLINE_FLASH_MS)
+            } finally {
+                showBackOnline = false
+            }
+        }
+        wasDown = down
+    }
+
     AnimatedVisibility(
-        visible = !online,
+        visible = health != ServerHealth.Healthy || showBackOnline,
         enter = expandVertically() + fadeIn(),
         exit = shrinkVertically() + fadeOut(),
     ) {
-        Row(
-            modifier = Modifier
-                .fillMaxWidth()
-                .background(MaterialTheme.colorScheme.errorContainer)
-                .padding(horizontal = 16.dp, vertical = 10.dp),
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(12.dp),
-        ) {
-            Icon(
-                imageVector = Lucide.CloudOff,
-                contentDescription = null,
-                tint = MaterialTheme.colorScheme.onErrorContainer,
-            )
-            Text(
-                text = "No connection — check Wi-Fi or mobile data.",
-                style = MaterialTheme.typography.bodyMedium,
-                color = MaterialTheme.colorScheme.onErrorContainer,
-            )
-        }
+        BannerContent(health = health, backOnline = showBackOnline)
     }
 }
+
+@Composable
+private fun BannerContent(health: ServerHealth, backOnline: Boolean) {
+    val scheme = MaterialTheme.colorScheme
+    val background: Color
+    val foreground: Color
+    when {
+        backOnline -> {
+            background = scheme.secondaryContainer
+            foreground = scheme.onSecondaryContainer
+        }
+        health == ServerHealth.Unstable -> {
+            background = scheme.surfaceVariant
+            foreground = scheme.onSurfaceVariant
+        }
+        else -> {
+            background = scheme.errorContainer
+            foreground = scheme.onErrorContainer
+        }
+    }
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .background(background)
+            .padding(horizontal = 16.dp, vertical = 10.dp),
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(12.dp),
+    ) {
+        Icon(imageVector = Lucide.CloudOff, contentDescription = null, tint = foreground)
+        Text(
+            text = bannerText(health, backOnline),
+            style = MaterialTheme.typography.bodyMedium,
+            color = foreground,
+        )
+    }
+}
+
+private fun bannerText(health: ServerHealth, backOnline: Boolean): String = when {
+    backOnline -> "Back online."
+    health == ServerHealth.Offline -> "No connection — check Wi-Fi or mobile data."
+    health == ServerHealth.ServerDown ->
+        "Server unreachable — your cached content is still available."
+    health == ServerHealth.Unstable -> "Reconnecting…"
+    else -> ""
+}

android/app/src/main/java/com/fabledsword/minstrel/home/data/HomeRepository.kt

@@ -39,6 +39,9 @@ import javax.inject.Singleton
  * pre-warms the top artists via [HomeArtistPrewarmer].
  */
 @Singleton
+// Per-section observe accessors (one per Home row) inflate the function
+// count past detekt's 11 default — accessor density, not complexity.
+@Suppress("TooManyFunctions")
 class HomeRepository @Inject constructor(
     private val homeIndexDao: CachedHomeIndexDao,
     private val metadataProvider: MetadataProvider,
@@ -76,6 +79,12 @@ class HomeRepository @Inject constructor(
     fun observeLastPlayedArtists(): Flow<List<HomeTile<ArtistRef>>> =
         observeArtistSection(SECTION_LAST_PLAYED_ARTISTS)
 
+    fun observeYouMightLikeAlbums(): Flow<List<HomeTile<AlbumRef>>> =
+        observeAlbumSection(SECTION_YOU_MIGHT_LIKE_ALBUMS)
+
+    fun observeYouMightLikeArtists(): Flow<List<HomeTile<ArtistRef>>> =
+        observeArtistSection(SECTION_YOU_MIGHT_LIKE_ARTISTS)
+
     /**
      * Pulls /api/home/index, replaces each cached_home_index section,
      * and pre-warms the top artists. The section Flows re-fire on the
@@ -88,7 +97,11 @@ class HomeRepository @Inject constructor(
         replaceSection(SECTION_REDISCOVER_ARTISTS, "artist", wire.rediscoverArtists)
         replaceSection(SECTION_MOST_PLAYED_TRACKS, "track", wire.mostPlayedTracks)
         replaceSection(SECTION_LAST_PLAYED_ARTISTS, "artist", wire.lastPlayedArtists)
-        prewarmer.warm(wire.rediscoverArtists + wire.lastPlayedArtists)
+        replaceSection(SECTION_YOU_MIGHT_LIKE_ALBUMS, "album", wire.youMightLikeAlbums)
+        replaceSection(SECTION_YOU_MIGHT_LIKE_ARTISTS, "artist", wire.youMightLikeArtists)
+        prewarmer.warm(
+            wire.rediscoverArtists + wire.lastPlayedArtists + wire.youMightLikeArtists,
+        )
     }
 
     private suspend fun replaceSection(section: String, entityType: String, ids: List<String>) {
@@ -148,5 +161,7 @@ class HomeRepository @Inject constructor(
         const val SECTION_REDISCOVER_ARTISTS = "rediscover_artists"
         const val SECTION_MOST_PLAYED_TRACKS = "most_played_tracks"
         const val SECTION_LAST_PLAYED_ARTISTS = "last_played_artists"
+        const val SECTION_YOU_MIGHT_LIKE_ALBUMS = "you_might_like_albums"
+        const val SECTION_YOU_MIGHT_LIKE_ARTISTS = "you_might_like_artists"
     }
 }

android/app/src/main/java/com/fabledsword/minstrel/home/ui/HomeScreen.kt

@@ -54,6 +54,7 @@ import com.composables.icons.lucide.History
 import com.composables.icons.lucide.Lucide
 import com.composables.icons.lucide.Music
 import com.fabledsword.minstrel.api.ErrorCopy
+import com.fabledsword.minstrel.connectivity.ServerHealth
 import com.fabledsword.minstrel.home.data.HomeRepository
 import com.fabledsword.minstrel.library.data.LibraryRepository
 import com.fabledsword.minstrel.library.widgets.AlbumCard
@@ -69,7 +70,7 @@ import com.fabledsword.minstrel.nav.ArtistDetail
 import com.fabledsword.minstrel.nav.Home
 import com.fabledsword.minstrel.nav.PlaylistDetail
 import com.fabledsword.minstrel.playlists.data.PlaylistsRepository
-import com.fabledsword.minstrel.playlists.data.toPlayableTrackRefs
+import com.fabledsword.minstrel.playlists.data.playPlaylistShuffled
 import com.fabledsword.minstrel.playlists.widgets.OfflinePoolCard
 import com.fabledsword.minstrel.playlists.widgets.PlaylistCard
 import com.fabledsword.minstrel.playlists.widgets.PlaylistPlaceholderCard
@@ -95,11 +96,9 @@ import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
-import kotlinx.coroutines.withTimeout
 import javax.inject.Inject
 
 private const val SHARE_STOP_TIMEOUT_MS = 5_000L
-private const val PLAYLIST_FETCH_TIMEOUT_MS = 8_000L
 private const val BOTTOM_PADDING_FOR_MINIPLAYER_DP = 140
 // Recently Added is laid out in a multi-row LazyHorizontalGrid that
 // scrolls as one panel (same pattern as Most Played). Two rows trades
@@ -117,6 +116,8 @@ data class HomeSections(
     val rediscoverArtists: List<HomeTile<ArtistRef>> = emptyList(),
     val mostPlayedTracks: List<HomeTile<TrackRef>> = emptyList(),
     val lastPlayedArtists: List<HomeTile<ArtistRef>> = emptyList(),
+    val youMightLikeAlbums: List<HomeTile<AlbumRef>> = emptyList(),
+    val youMightLikeArtists: List<HomeTile<ArtistRef>> = emptyList(),
 ) {
     val isAllEmpty: Boolean
         get() = playlists.isEmpty() &&
@@ -124,7 +125,9 @@ data class HomeSections(
             rediscoverAlbums.isEmpty() &&
             rediscoverArtists.isEmpty() &&
             mostPlayedTracks.isEmpty() &&
-            lastPlayedArtists.isEmpty()
+            lastPlayedArtists.isEmpty() &&
+            youMightLikeAlbums.isEmpty() &&
+            youMightLikeArtists.isEmpty()
 }
 
 // ─── ViewModel ───────────────────────────────────────────────────────
@@ -136,7 +139,7 @@ class HomeViewModel @Inject constructor(
     private val libraryRepository: LibraryRepository,
     private val player: com.fabledsword.minstrel.player.PlayerController,
     private val shuffleSource: com.fabledsword.minstrel.cache.ShuffleSource,
-    connectivity: com.fabledsword.minstrel.connectivity.ConnectivityObserver,
+    networkStatus: com.fabledsword.minstrel.connectivity.NetworkStatusController,
 ) : ViewModel() {
 
     private val systemStatusInternal = MutableStateFlow(SystemPlaylistsStatus())
@@ -144,9 +147,13 @@ class HomeViewModel @Inject constructor(
     /** System-playlist build status for the Home placeholder cards. */
     val systemStatus: StateFlow<SystemPlaylistsStatus> = systemStatusInternal.asStateFlow()
 
-    /** True when the device has no usable internet — gates the offline-pool cards. */
-    val offline: StateFlow<Boolean> = connectivity.online
-        .map { !it }
+    /**
+     * Cache-only when there's no link OR the server is unreachable. Reads the
+     * unified [NetworkStatusController] (not the raw device link) so Home reacts
+     * to ServerDown too; the transient Unstable state stays calm (not offline).
+     */
+    val offline: StateFlow<Boolean> = networkStatus.state
+        .map { it == ServerHealth.Offline || it == ServerHealth.ServerDown }
         .stateIn(
             scope = viewModelScope,
             started = SharingStarted.WhileSubscribed(SHARE_STOP_TIMEOUT_MS),
@@ -259,37 +266,9 @@ class HomeViewModel @Inject constructor(
      */
     suspend fun playPlaylist(playlist: PlaylistRef) {
         viewModelScope.launch {
-            val detail = try {
-                withTimeout(PLAYLIST_FETCH_TIMEOUT_MS) {
-                    if (playlist.refreshable && playlist.systemVariant != null) {
-                        playlistsRepository.systemShuffle(playlist.systemVariant!!)
-                    } else {
-                        playlistsRepository.refreshDetail(playlist.id)
-                    }
-                }
-            } catch (
-                @Suppress("SwallowedException") _: kotlinx.coroutines.TimeoutCancellationException,
-            ) {
-                poolMessages.trySend("Couldn't load playlist - check your connection")
-                return@launch
-            } catch (
-                @Suppress("TooGenericExceptionCaught") e: Throwable,
-            ) {
-                poolMessages.trySend(
-                    "Couldn't load playlist: ${ErrorCopy.fromThrowable(e)}",
-                )
-                return@launch
+            playPlaylistShuffled(playlist, playlistsRepository, player) {
+                poolMessages.trySend(it)
             }
-            // Shared with PlaylistDetailViewModel.play - filters out
-            // unplayable rows (missing trackId or empty streamUrl) so the
-            // queue can't end up with tracks Media3 silently rejects.
-            val tracks = detail.tracks.toPlayableTrackRefs()
-            if (tracks.isEmpty()) {
-                poolMessages.trySend("Mix isn't ready yet - try again in a moment")
-                return@launch
-            }
-            val source = if (playlist.refreshable) "playlist:${playlist.systemVariant}" else null
-            player.setQueue(tracks, initialIndex = 0, source = source)
         }.join()
     }
 
@@ -314,13 +293,14 @@ class HomeViewModel @Inject constructor(
         combineHomeFlows().asCacheFirstStateFlow(viewModelScope)
 
     /**
-     * Five home-section flows merged into the sections struct without
-     * playlists; then merged with the playlists flow in [combineHomeFlows].
-     * Splitting it like this keeps each combine call inside the
-     * coroutines built-in arity limit (5) and avoids the typed-vararg
-     * acrobatics needed for a 6-flow combine across heterogeneous types.
+     * The core five section flows merged into the sections struct. Split
+     * out so each combine call stays inside the coroutines built-in arity
+     * limit (5) and avoids the typed-vararg acrobatics a wider combine
+     * across heterogeneous types would need. [observeHomeSections] then
+     * folds in the two you-might-like flows, and [combineHomeFlows] the
+     * playlists flow.
      */
-    private fun observeHomeSections() = combine(
+    private fun observeCoreSections() = combine(
         homeRepository.observeRecentlyAddedAlbums(),
         homeRepository.observeRediscoverAlbums(),
         homeRepository.observeRediscoverArtists(),
@@ -336,6 +316,14 @@ class HomeViewModel @Inject constructor(
         )
     }
 
+    private fun observeHomeSections() = combine(
+        observeCoreSections(),
+        homeRepository.observeYouMightLikeAlbums(),
+        homeRepository.observeYouMightLikeArtists(),
+    ) { core, ymlAlbums, ymlArtists ->
+        core.copy(youMightLikeAlbums = ymlAlbums, youMightLikeArtists = ymlArtists)
+    }
+
     private fun combineHomeFlows() =
         observeHomeSections().combine(playlistsRepository.observeAll()) { sections, playlists ->
             val merged = sections.copy(playlists = playlists)
@@ -488,6 +476,14 @@ private fun HomeSuccessContent(
                 onPlayPlaylist = onPlayPlaylist,
             )
         }
+        youMightLikeSection(
+            albums = sections.youMightLikeAlbums,
+            artists = sections.youMightLikeArtists,
+            onAlbumClick = onAlbumClick,
+            onArtistClick = onArtistClick,
+            onPlayAlbum = onPlayAlbum,
+            onPlayArtist = onPlayArtist,
+        )
         recentlyAddedSection(sections.recentlyAddedAlbums, onAlbumClick, onPlayAlbum)
         rediscoverSection(
             albums = sections.rediscoverAlbums,
@@ -692,6 +688,61 @@ private fun RediscoverBlock(
     }
 }
 
+/**
+ * "You might like" — in-library albums/artists predicted from the user's
+ * taste that they don't actively spin (server section, daily-built, cold-
+ * start gated). Sits directly under the system-playlists row. Same
+ * albums-then-artists block shape as Rediscover; the artist sub-row drops
+ * its title when an album sub-row precedes it so the two read as one section.
+ */
+private fun LazyListScope.youMightLikeSection(
+    albums: List<HomeTile<AlbumRef>>,
+    artists: List<HomeTile<ArtistRef>>,
+    onAlbumClick: (String) -> Unit,
+    onArtistClick: (String) -> Unit,
+    onPlayAlbum: suspend (String) -> Unit,
+    onPlayArtist: suspend (String) -> Unit,
+) {
+    item {
+        if (albums.isNotEmpty() || artists.isNotEmpty()) {
+            YouMightLikeBlock(
+                albums = albums,
+                artists = artists,
+                onAlbumClick = onAlbumClick,
+                onArtistClick = onArtistClick,
+                onPlayAlbum = onPlayAlbum,
+                onPlayArtist = onPlayArtist,
+            )
+        } else {
+            EmptySection(
+                title = "You might like",
+                body = "We're still learning your taste — keep listening and " +
+                    "picks you might like will show up here.",
+            )
+        }
+    }
+}
+
+@Composable
+private fun YouMightLikeBlock(
+    albums: List<HomeTile<AlbumRef>>,
+    artists: List<HomeTile<ArtistRef>>,
+    onAlbumClick: (String) -> Unit,
+    onArtistClick: (String) -> Unit,
+    onPlayAlbum: suspend (String) -> Unit,
+    onPlayArtist: suspend (String) -> Unit,
+) {
+    Column {
+        if (albums.isNotEmpty()) {
+            AlbumsRow("You might like", albums, onAlbumClick, onPlayAlbum)
+        }
+        if (artists.isNotEmpty()) {
+            val title = if (albums.isEmpty()) "You might like" else ""
+            ArtistsRow(title, artists, onArtistClick, onPlayArtist)
+        }
+    }
+}
+
 @Composable
 private fun AlbumsRow(
     title: String,
@@ -731,18 +782,19 @@ private fun PlaylistsRow(
                     icon = iconForPool(item.kind),
                     onClick = { onPlayPool(item.kind) },
                 )
-                is PlaylistRowItem.Real -> PlaylistCard(
-                    playlist = item.playlist,
-                    onClick = { onPlaylistClick(item.playlist.id) },
-                    onPlay = { onPlayPlaylist(item.playlist) },
-                    // Match Flutter: refreshable system playlists need
-                    // the live server endpoints, so disable their play
-                    // overlay when offline (user can still tap into the
-                    // detail and shuffle all from cache). User playlists
-                    // play from cache + survive offline.
-                    playEnabled = item.playlist.trackCount > 0 &&
-                        !(offline && item.playlist.refreshable),
-                )
+                is PlaylistRowItem.Real -> {
+                    // Greyed offline when the tile needs the live server or
+                    // isn't fully cached — dimmed but still tappable into the
+                    // detail to shuffle whatever subset is cached.
+                    val greyed = offline && item.playlist.unavailableOffline
+                    PlaylistCard(
+                        playlist = item.playlist,
+                        onClick = { onPlaylistClick(item.playlist.id) },
+                        onPlay = { onPlayPlaylist(item.playlist) },
+                        playEnabled = item.playlist.trackCount > 0 && !greyed,
+                        greyed = greyed,
+                    )
+                }
                 is PlaylistRowItem.Placeholder -> PlaylistPlaceholderCard(
                     label = item.label,
                     variant = item.variant,
@@ -758,7 +810,7 @@ private fun iconForPool(kind: OfflinePoolKind) = when (kind) {
 }
 
 /** A cache-backed offline pool, a real playlist tile, or a not-yet-generated slot. */
-private sealed interface PlaylistRowItem {
+internal sealed interface PlaylistRowItem {
     data class OfflinePool(val kind: OfflinePoolKind) : PlaylistRowItem
     data class Real(val playlist: PlaylistRef) : PlaylistRowItem
     data class Placeholder(val label: String, val variant: String) : PlaylistRowItem
@@ -771,55 +823,81 @@ enum class OfflinePoolKind(val label: String) {
 }
 
 /**
- * Builds the Home Playlists row. When [offline], the two cache-backed
- * pool cards (Recently played, Liked) lead the row. Then For You +
- * Discover + 3× Songs-like fixed slots (real card when generated,
- * placeholder otherwise), then the secondary system kinds (deep cuts /
- * rediscover / new for you / on this day / first listens) when they
- * exist — no placeholders for these since they're conditional on
- * library shape, not guaranteed singletons. Finally user-owned
- * playlists.
+ * Builds the Home Playlists row.
+ *
+ * Online: For You + Discover + 3× Songs-like fixed slots (real card when
+ * generated, placeholder otherwise), then the secondary system kinds (deep cuts
+ * / rediscover / new for you / on this day / first listens) when they exist —
+ * no placeholders for these since they're conditional on library shape — then
+ * user-owned playlists.
+ *
+ * Offline: the two cache-backed pools (Recently played, Liked) lead, then the
+ * same real playlists in curated order but stably partitioned fully-cached
+ * first / greyed after, and the "building/pending" placeholders are dropped
+ * (they need the server to generate, so they're meaningless offline).
  *
  * Diverges from Flutter (`flutter_client/lib/library/home_screen.dart`
  * `_buildPlaylistsRow`) which only shows the 5 fixed slots and never
  * surfaces the secondary kinds on Home. Operator authorized the
  * divergence on 2026-06-01; web UI catch-up tracked as task #53.
  */
-private fun buildPlaylistsRow(
+internal fun buildPlaylistsRow(
     owned: List<PlaylistRef>,
     status: SystemPlaylistsStatus,
     offline: Boolean,
+): List<PlaylistRowItem> {
+    if (!offline) return buildOnlineRow(owned, status)
+    val out = mutableListOf<PlaylistRowItem>(
+        PlaylistRowItem.OfflinePool(OfflinePoolKind.RECENTLY_PLAYED),
+        PlaylistRowItem.OfflinePool(OfflinePoolKind.LIKED),
+    )
+    val (available, greyed) = orderedRealPlaylists(owned).partition { !it.unavailableOffline }
+    (available + greyed).forEach { out += PlaylistRowItem.Real(it) }
+    return out
+}
+
+/** The online layout: fixed system slots (with placeholders), secondary, user. */
+private fun buildOnlineRow(
+    owned: List<PlaylistRef>,
+    status: SystemPlaylistsStatus,
 ): List<PlaylistRowItem> {
     val out = mutableListOf<PlaylistRowItem>()
-    if (offline) {
-        out += PlaylistRowItem.OfflinePool(OfflinePoolKind.RECENTLY_PLAYED)
-        out += PlaylistRowItem.OfflinePool(OfflinePoolKind.LIKED)
-    }
     out += owned.firstOrNull { it.systemVariant == "for_you" }
         ?.let { PlaylistRowItem.Real(it) }
         ?: PlaylistRowItem.Placeholder("For You", variantFor("for-you", status))
     out += owned.firstOrNull { it.systemVariant == "discover" }
         ?.let { PlaylistRowItem.Real(it) }
         ?: PlaylistRowItem.Placeholder("Discover", variantFor("discover", status))
-    val songsLike = owned.filter { it.systemVariant == "songs_like_artist" }.take(3)
+    val songsLike = owned.filter { it.systemVariant == "songs_like_artist" }.take(SONGS_LIKE_SLOTS)
     for (i in 0 until SONGS_LIKE_SLOTS) {
         out += songsLike.getOrNull(i)
             ?.let { PlaylistRowItem.Real(it) }
             ?: PlaylistRowItem.Placeholder("Songs like…", variantFor("songs-like", status))
     }
-    // Secondary system kinds in server-registry order. Only included
-    // when actually generated — these depend on library shape (Deep
-    // cuts needs deep albums, On this day needs prior history, etc.)
-    // so a missing one means "not enough data" rather than "still
-    // building".
     for (variant in SECONDARY_SYSTEM_VARIANTS) {
-        owned.firstOrNull { it.systemVariant == variant }
-            ?.let { out += PlaylistRowItem.Real(it) }
+        owned.firstOrNull { it.systemVariant == variant }?.let { out += PlaylistRowItem.Real(it) }
     }
     owned.filter { it.systemVariant == null }.forEach { out += PlaylistRowItem.Real(it) }
     return out
 }
 
+/**
+ * Curated real-playlist order (system primaries, then secondary, then user).
+ * Must mirror [buildOnlineRow]'s slot order — the offline row reuses this and
+ * only differs by dropping placeholders + partitioning available-first.
+ */
+private fun orderedRealPlaylists(owned: List<PlaylistRef>): List<PlaylistRef> {
+    val out = mutableListOf<PlaylistRef>()
+    owned.firstOrNull { it.systemVariant == "for_you" }?.let { out += it }
+    owned.firstOrNull { it.systemVariant == "discover" }?.let { out += it }
+    out += owned.filter { it.systemVariant == "songs_like_artist" }.take(SONGS_LIKE_SLOTS)
+    for (variant in SECONDARY_SYSTEM_VARIANTS) {
+        owned.firstOrNull { it.systemVariant == variant }?.let { out += it }
+    }
+    owned.filter { it.systemVariant == null }.forEach { out += it }
+    return out
+}
+
 private fun variantFor(slot: String, s: SystemPlaylistsStatus): String = when {
     s.inFlight -> "building"
     s.lastError != null -> "failed"

android/app/src/main/java/com/fabledsword/minstrel/library/data/LibraryRepository.kt

@@ -105,6 +105,22 @@ class LibraryRepository @Inject constructor(
     suspend fun fetchArtistTracks(id: String): List<TrackRef> =
         api.getArtistTracks(id).map { it.toDomain() }
 
+    /**
+     * Pulls related artists for the ArtistDetail "Similar artists"
+     * strip. Network-only — non-critical UI, callers swallow failures
+     * and render nothing rather than blocking the screen.
+     */
+    suspend fun fetchSimilarArtists(id: String): List<ArtistRef> =
+        api.getSimilarArtists(id).map { it.toDomain() }
+
+    /**
+     * Pulls the artist's top tracks for the ArtistDetail "Top tracks"
+     * panel. Network-only; tapping a row plays this exact list as a
+     * queue, so no persistence is needed.
+     */
+    suspend fun fetchArtistTopTracks(id: String): List<TrackRef> =
+        api.getArtistTopTracks(id).map { it.toDomain() }
+
     /**
      * Pulls the album detail (AlbumRef + tracks), persists both, and
      * returns the in-memory snapshot. Lets the AlbumDetail screen

android/app/src/main/java/com/fabledsword/minstrel/library/ui/AlbumDetailScreen.kt

@@ -109,8 +109,11 @@ private fun AlbumDetailStateContent(
     playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel,
     navController: NavHostController,
 ) {
-    Crossfade(targetState = state, label = "album-detail") { s ->
-        when (s) {
+    // Crossfade keyed on `state::class` so a Success → fresh Success
+    // refresh (same kind, new detail) doesn't re-fade the whole body;
+    // only Loading ↔ Success ↔ Error transitions animate.
+    Crossfade(targetState = state::class, label = "album-detail") { _ ->
+        when (val s = state) {
             is AlbumDetailUiState.Loading ->
                 if (s.seed != null) SeededAlbumLoading(s.seed) else SkeletonTrackList()
             is AlbumDetailUiState.Error -> EmptyState(

android/app/src/main/java/com/fabledsword/minstrel/library/ui/AlbumDetailViewModel.kt

@@ -18,7 +18,6 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
-import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import javax.inject.Inject
@@ -56,8 +55,7 @@ class AlbumDetailViewModel @Inject constructor(
             )
 
     val likedTrackIds: StateFlow<Set<String>> =
-        likes.observeLikedTracks()
-            .map { tracks -> tracks.mapTo(mutableSetOf()) { it.id } }
+        likes.observeLikedTrackIds()
             .stateIn(
                 scope = viewModelScope,
                 started = SharingStarted.WhileSubscribed(SHARE_STOP_TIMEOUT_MS),

android/app/src/main/java/com/fabledsword/minstrel/library/ui/ArtistDetailScreen.kt

@@ -1,3 +1,5 @@
+@file:Suppress("TooManyFunctions") // Compose screen + private helper composables
+
 package com.fabledsword.minstrel.library.ui
 
 import androidx.compose.animation.Crossfade
@@ -18,6 +20,7 @@ import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.GridItemSpan
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.foundation.lazy.items as lazyItems
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material3.Button
 import androidx.compose.material3.ExperimentalMaterial3Api
@@ -46,21 +49,27 @@ import com.composables.icons.lucide.Lucide
 import com.composables.icons.lucide.Play
 import com.composables.icons.lucide.User
 import com.fabledsword.minstrel.library.widgets.AlbumCard
-import com.fabledsword.minstrel.models.ArtistDetailRef
+import com.fabledsword.minstrel.library.widgets.ArtistCard
 import com.fabledsword.minstrel.models.ArtistRef
+import com.fabledsword.minstrel.models.TrackRef
 import com.fabledsword.minstrel.models.albumCoverPath
 import com.fabledsword.minstrel.nav.AlbumDetail
+import com.fabledsword.minstrel.nav.ArtistDetail
+import com.fabledsword.minstrel.shared.formatDuration
 import com.fabledsword.minstrel.shared.widgets.EmptyState
+import com.fabledsword.minstrel.shared.widgets.HorizontalScrollRow
 import com.fabledsword.minstrel.shared.widgets.LikeButton
 import com.fabledsword.minstrel.shared.widgets.PullToRefreshScaffold
 import com.fabledsword.minstrel.shared.widgets.ServerImage
 import com.fabledsword.minstrel.shared.widgets.SkeletonAlbumTile
+import com.fabledsword.minstrel.shared.widgets.TrackRow
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun ArtistDetailScreen(
     navController: NavHostController,
     viewModel: ArtistDetailViewModel = hiltViewModel(),
+    playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel = hiltViewModel(),
 ) {
     val state by viewModel.uiState.collectAsStateWithLifecycle()
     val snackbarHostState = remember { SnackbarHostState() }
@@ -87,8 +96,11 @@ fun ArtistDetailScreen(
             onRefresh = { viewModel.refresh().join() },
             modifier = Modifier.fillMaxSize().padding(inner),
         ) {
-            Crossfade(targetState = state, label = "artist-detail") { s ->
-                when (s) {
+            // Crossfade keyed on `state::class` so a Success → fresh
+            // Success refresh (same kind, new detail) doesn't re-fade
+            // the body; only Loading ↔ Success ↔ Error animate.
+            Crossfade(targetState = state::class, label = "artist-detail") { _ ->
+                when (val s = state) {
                     is ArtistDetailUiState.Loading ->
                         if (s.seed != null) {
                             SeededArtistLoading(s.seed)
@@ -99,23 +111,35 @@ fun ArtistDetailScreen(
                         title = "Couldn't load artist",
                         body = s.message,
                     )
-                    is ArtistDetailUiState.Success -> {
-                        val artistLiked by viewModel.artistLiked
-                            .collectAsStateWithLifecycle()
-                        ArtistBody(
-                            detail = s.detail,
-                            artistLiked = artistLiked,
-                            onPlay = viewModel::playArtist,
-                            onToggleLike = viewModel::toggleLikeArtist,
-                            onAlbumClick = { id -> navController.navigate(AlbumDetail(id)) },
-                        )
-                    }
+                    is ArtistDetailUiState.Success ->
+                        ArtistSuccessBody(s, viewModel, playerViewModel, navController)
                 }
             }
         }
     }
 }
 
+@Composable
+private fun ArtistSuccessBody(
+    state: ArtistDetailUiState.Success,
+    viewModel: ArtistDetailViewModel,
+    playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel,
+    navController: NavHostController,
+) {
+    val artistLiked by viewModel.artistLiked.collectAsStateWithLifecycle()
+    val playerState by playerViewModel.uiState.collectAsStateWithLifecycle()
+    ArtistBody(
+        state = state,
+        artistLiked = artistLiked,
+        playingTrackId = playerState.currentTrack?.id,
+        onPlay = viewModel::playArtist,
+        onToggleLike = viewModel::toggleLikeArtist,
+        onAlbumClick = { id -> navController.navigate(AlbumDetail(id)) },
+        onTopTrackClick = viewModel::playTopTracks,
+        onSimilarArtistClick = { id -> navController.navigate(ArtistDetail(id)) },
+    )
+}
+
 private fun titleFor(state: ArtistDetailUiState): String = when (state) {
     is ArtistDetailUiState.Success -> state.detail.artist.name
     is ArtistDetailUiState.Loading -> state.seed?.name ?: "Artist"
@@ -124,12 +148,16 @@ private fun titleFor(state: ArtistDetailUiState): String = when (state) {
 
 @Composable
 private fun ArtistBody(
-    detail: ArtistDetailRef,
+    state: ArtistDetailUiState.Success,
     artistLiked: Boolean,
+    playingTrackId: String?,
     onPlay: () -> Unit,
     onToggleLike: () -> Unit,
     onAlbumClick: (String) -> Unit,
+    onTopTrackClick: (Int) -> Unit,
+    onSimilarArtistClick: (String) -> Unit,
 ) {
+    val detail = state.detail
     LazyVerticalGrid(
         columns = GridCells.Adaptive(minSize = 176.dp),
         modifier = Modifier.fillMaxSize(),
@@ -146,6 +174,23 @@ private fun ArtistBody(
                 onToggleLike = onToggleLike,
             )
         }
+        if (state.topTracks.isNotEmpty()) {
+            item(span = { GridItemSpan(maxLineSpan) }) {
+                TopTracksPanel(
+                    tracks = state.topTracks,
+                    playingTrackId = playingTrackId,
+                    onTrackClick = onTopTrackClick,
+                )
+            }
+        }
+        if (state.similarArtists.isNotEmpty()) {
+            item(span = { GridItemSpan(maxLineSpan) }) {
+                SimilarArtistsStrip(
+                    artists = state.similarArtists,
+                    onArtistClick = onSimilarArtistClick,
+                )
+            }
+        }
         if (detail.albums.isEmpty()) {
             item(span = { GridItemSpan(maxLineSpan) }) {
                 EmptyAlbumsHint()
@@ -158,6 +203,67 @@ private fun ArtistBody(
     }
 }
 
+@Composable
+private fun TopTracksPanel(
+    tracks: List<TrackRef>,
+    playingTrackId: String?,
+    onTrackClick: (Int) -> Unit,
+) {
+    Column(modifier = Modifier.fillMaxWidth()) {
+        Text(
+            text = "Top tracks",
+            style = MaterialTheme.typography.titleLarge,
+            color = MaterialTheme.colorScheme.onBackground,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
+        )
+        tracks.forEachIndexed { index, track ->
+            TopTrackRow(
+                track = track,
+                nowPlaying = track.id == playingTrackId,
+                onClick = { onTrackClick(index) },
+            )
+        }
+    }
+}
+
+@Composable
+private fun TopTrackRow(
+    track: TrackRef,
+    nowPlaying: Boolean,
+    onClick: () -> Unit,
+) {
+    TrackRow(
+        title = track.title,
+        artist = track.artistName,
+        trackId = track.id,
+        onClick = onClick,
+        nowPlaying = nowPlaying,
+        trailing = {
+            Text(
+                text = formatDuration(track.durationSec, zero = "--:--"),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.padding(start = 12.dp),
+            )
+        },
+    )
+}
+
+@Composable
+private fun SimilarArtistsStrip(
+    artists: List<ArtistRef>,
+    onArtistClick: (String) -> Unit,
+) {
+    HorizontalScrollRow(title = "Similar artists") {
+        lazyItems(items = artists, key = { it.id }) { artist ->
+            ArtistCard(
+                artist = artist,
+                onClick = { onArtistClick(artist.id) },
+            )
+        }
+    }
+}
+
 @Composable
 private fun ArtistHeader(
     artist: ArtistRef,

android/app/src/main/java/com/fabledsword/minstrel/library/ui/ArtistDetailViewModel.kt

@@ -9,6 +9,7 @@ import com.fabledsword.minstrel.library.data.LibraryRepository
 import com.fabledsword.minstrel.likes.data.LikesRepository
 import com.fabledsword.minstrel.models.ArtistDetailRef
 import com.fabledsword.minstrel.models.ArtistRef
+import com.fabledsword.minstrel.models.TrackRef
 import com.fabledsword.minstrel.nav.ArtistDetail
 import com.fabledsword.minstrel.nav.DetailSeedCache
 import com.fabledsword.minstrel.player.PlayerController
@@ -23,13 +24,18 @@ import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
+import timber.log.Timber
 import javax.inject.Inject
 
 private const val SHARE_STOP_TIMEOUT_MS = 5_000L
 
 sealed interface ArtistDetailUiState {
     data class Loading(val seed: ArtistRef? = null) : ArtistDetailUiState
-    data class Success(val detail: ArtistDetailRef) : ArtistDetailUiState
+    data class Success(
+        val detail: ArtistDetailRef,
+        val similarArtists: List<ArtistRef> = emptyList(),
+        val topTracks: List<TrackRef> = emptyList(),
+    ) : ArtistDetailUiState
     data class Error(val message: String) : ArtistDetailUiState
 }
 
@@ -82,6 +88,7 @@ class ArtistDetailViewModel @Inject constructor(
         try {
             val detail = repository.refreshArtistDetail(artistId)
             internal.value = ArtistDetailUiState.Success(detail)
+            loadSecondarySections()
         } catch (
             @Suppress("TooGenericExceptionCaught") e: Throwable,
         ) {
@@ -89,6 +96,31 @@ class ArtistDetailViewModel @Inject constructor(
         }
     }
 
+    /**
+     * Pulls the non-critical "Similar artists" + "Top tracks" sections
+     * and folds them into the live Success state. Each failure is
+     * swallowed (logged only) — these sections render absent rather than
+     * blocking, so the core artist view never depends on them.
+     */
+    private suspend fun loadSecondarySections() {
+        val similar = sectionOrEmpty { repository.fetchSimilarArtists(artistId) }
+        val top = sectionOrEmpty { repository.fetchArtistTopTracks(artistId) }
+        val current = internal.value
+        if (current is ArtistDetailUiState.Success) {
+            internal.value = current.copy(similarArtists = similar, topTracks = top)
+        }
+    }
+
+    private inline fun <T> sectionOrEmpty(block: () -> List<T>): List<T> =
+        try {
+            block()
+        } catch (
+            @Suppress("TooGenericExceptionCaught") e: Throwable,
+        ) {
+            Timber.w(e, "Artist secondary section fetch failed for %s", artistId)
+            emptyList()
+        }
+
     /**
      * Pull every track across the artist's albums, shuffle, and start
      * playing. Mirrors Flutter's artist Play button — pressing Play on
@@ -118,4 +150,20 @@ class ArtistDetailViewModel @Inject constructor(
             }
         }
     }
+
+    /**
+     * Plays the loaded "Top tracks" list starting at [index] — the top
+     * tracks are themselves the playable queue (mirrors the web client's
+     * sectionTracks = top-tracks behaviour). No network round-trip; the
+     * list is already in the Success state.
+     */
+    fun playTopTracks(index: Int) {
+        val tracks = (internal.value as? ArtistDetailUiState.Success)?.topTracks.orEmpty()
+        if (tracks.isEmpty()) return
+        player.setQueue(
+            tracks = tracks,
+            initialIndex = index.coerceIn(0, tracks.lastIndex),
+            source = "artist-top:$artistId",
+        )
+    }
 }

android/app/src/main/java/com/fabledsword/minstrel/library/ui/LibraryScreen.kt

@@ -4,7 +4,6 @@ package com.fabledsword.minstrel.library.ui
 
 import androidx.compose.animation.Crossfade
 import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.fillMaxSize
@@ -12,6 +11,8 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.foundation.pager.HorizontalPager
+import androidx.compose.foundation.pager.rememberPagerState
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -22,11 +23,10 @@ import androidx.compose.material3.Tab
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableIntStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.launch
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation.NavHostController
@@ -69,8 +69,12 @@ fun LibraryScreen(
     navController: NavHostController,
     viewModel: LibraryViewModel = hiltViewModel(),
 ) {
-    var selectedTab by remember { mutableIntStateOf(0) }
     val tabs = LIBRARY_TABS
+    // HorizontalPager owns the active-tab state — the TabRow reads
+    // pagerState.currentPage and animateScrollToPage drives it on tap,
+    // so swipe and tap stay in sync.
+    val pagerState = rememberPagerState(pageCount = { tabs.size })
+    val scope = rememberCoroutineScope()
 
     Scaffold(
         modifier = Modifier.fillMaxSize(),
@@ -91,13 +95,13 @@ fun LibraryScreen(
                     },
                 )
                 PrimaryScrollableTabRow(
-                    selectedTabIndex = selectedTab,
+                    selectedTabIndex = pagerState.currentPage,
                     edgePadding = 16.dp,
                 ) {
                     tabs.forEachIndexed { index, label ->
                         Tab(
-                            selected = selectedTab == index,
-                            onClick = { selectedTab = index },
+                            selected = pagerState.currentPage == index,
+                            onClick = { scope.launch { pagerState.animateScrollToPage(index) } },
                             text = { Text(label) },
                         )
                     }
@@ -105,8 +109,11 @@ fun LibraryScreen(
             }
         },
     ) { inner ->
-        Box(modifier = Modifier.fillMaxSize().padding(inner)) {
-            when (selectedTab) {
+        HorizontalPager(
+            state = pagerState,
+            modifier = Modifier.fillMaxSize().padding(inner),
+        ) { page ->
+            when (page) {
                 TAB_ARTISTS -> ArtistsTab(viewModel = viewModel, navController = navController)
                 TAB_ALBUMS -> AlbumsTab(viewModel = viewModel, navController = navController)
                 TAB_HISTORY -> HistoryTab(
@@ -135,8 +142,13 @@ private fun ArtistsTab(
 ) {
     val state by viewModel.uiState.collectAsStateWithLifecycle()
     PullToRefreshScaffold(onRefresh = { viewModel.refresh().join() }) {
-        Crossfade(targetState = state, label = "library-artists") { s ->
-            when (s) {
+        // Crossfade is keyed on `state::class` (not the whole state)
+        // so a refresh that emits a fresh UiState.Success — same kind,
+        // new data — doesn't re-fade the entire grid. Only Loading ↔
+        // Success ↔ Error ↔ Empty transitions animate; row-level diff
+        // is owned by LazyVerticalGrid via its item keys.
+        Crossfade(targetState = state::class, label = "library-artists") { _ ->
+            when (val s = state) {
                 UiState.Loading -> SkeletonArtistsGrid()
                 UiState.Empty -> EmptyState(
                     title = "No artists yet",
@@ -163,8 +175,8 @@ private fun AlbumsTab(
 ) {
     val state by viewModel.uiState.collectAsStateWithLifecycle()
     PullToRefreshScaffold(onRefresh = { viewModel.refresh().join() }) {
-        Crossfade(targetState = state, label = "library-albums") { s ->
-            when (s) {
+        Crossfade(targetState = state::class, label = "library-albums") { _ ->
+            when (val s = state) {
                 UiState.Loading -> SkeletonAlbumsGrid()
                 UiState.Empty -> EmptyState(
                     title = "No albums yet",

android/app/src/main/java/com/fabledsword/minstrel/likes/data/LikesRepository.kt

@@ -1,19 +1,23 @@
 package com.fabledsword.minstrel.likes.data
 
 import com.fabledsword.minstrel.api.endpoints.LikesApi
+import com.fabledsword.minstrel.auth.AuthController
 import com.fabledsword.minstrel.cache.db.dao.CachedAlbumDao
 import com.fabledsword.minstrel.cache.db.dao.CachedArtistDao
 import com.fabledsword.minstrel.cache.db.dao.CachedLikeDao
 import com.fabledsword.minstrel.cache.db.dao.CachedTrackDao
 import com.fabledsword.minstrel.cache.db.entities.CachedLikeEntity
 import com.fabledsword.minstrel.cache.mutations.MutationQueue
+import com.fabledsword.minstrel.di.ApplicationScope
 import com.fabledsword.minstrel.library.data.toDomain
 import com.fabledsword.minstrel.models.AlbumRef
 import com.fabledsword.minstrel.models.ArtistRef
 import com.fabledsword.minstrel.models.TrackRef
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.launch
 import retrofit2.Retrofit
 import retrofit2.create
 import javax.inject.Inject
@@ -24,11 +28,14 @@ import javax.inject.Singleton
  * Flutter `likesControllerProvider` + `cached_likes`-driven Liked tab
  * pattern.
  *
- * Local `userId` discriminator is a constant for now (`LOCAL_USER_ID`)
- * because the AuthController hookup lands with Phase 11. Single-user
- * device is the only shape we target; if multi-tenant on one device
- * ever shows up, swap this constant for `AuthStore.userId.value`
- * everywhere and migrate the cached_likes rows.
+ * Local `userId` discriminator is the server-side user UUID
+ * (resolved via [AuthController.currentUser]); falls back to
+ * [ANONYMOUS_USER_ID] when no user is signed in so existing local
+ * cache rows from pre-#576 builds remain queryable until the first
+ * authenticated [refreshIds] call overwrites them. On user-switch
+ * (sign-out / sign-in as different user) the OUTGOING user's
+ * cached_likes rows are wiped so they don't leak into the new
+ * session — drift #576 audit caught the leak.
  *
  * Write path follows `feedback_offline_first_for_server_writes` —
  * never fire-and-forget:
@@ -48,33 +55,78 @@ class LikesRepository @Inject constructor(
     private val artistDao: CachedArtistDao,
     private val trackDao: CachedTrackDao,
     private val mutationQueue: MutationQueue,
+    private val authController: AuthController,
+    @ApplicationScope private val scope: CoroutineScope,
     retrofit: Retrofit,
 ) {
     private val api: LikesApi = retrofit.create()
 
+    init {
+        // Drift #576: clear the outgoing user's cached_likes rows
+        // when the signed-in user changes. Mostly a hygiene fix —
+        // discriminator-based queries already prevent the wrong
+        // user from SEEING leaked rows, but without this the rows
+        // pile up forever as different accounts sign in/out on the
+        // same device.
+        scope.launch {
+            var previousId: String? = null
+            authController.currentUser.collect { user ->
+                val newId = user?.id
+                val prev = previousId
+                if (prev != null && prev != newId) {
+                    likeDao.clearForUser(prev)
+                }
+                previousId = newId
+            }
+        }
+    }
+
+    /**
+     * Server-user-uuid for the current session, or [ANONYMOUS_USER_ID]
+     * fallback when there's no signed-in user. Used as the
+     * `cached_likes.userId` discriminator so each account's likes are
+     * stored under its own bucket.
+     */
+    private fun currentUserId(): String =
+        authController.currentUser.value?.id ?: ANONYMOUS_USER_ID
+
     // ── Reads ─────────────────────────────────────────────────────────
 
     fun observeLikedArtists(): Flow<List<ArtistRef>> =
-        likeDao.observeLikedIdsOfType(LOCAL_USER_ID, ENTITY_ARTIST).map { ids ->
+        likeDao.observeLikedIdsOfType(currentUserId(), ENTITY_ARTIST).map { ids ->
             ids.mapNotNull { artistDao.getById(it)?.toDomain() }
         }
 
     fun observeLikedAlbums(): Flow<List<AlbumRef>> =
-        likeDao.observeLikedIdsOfType(LOCAL_USER_ID, ENTITY_ALBUM).map { ids ->
+        likeDao.observeLikedIdsOfType(currentUserId(), ENTITY_ALBUM).map { ids ->
             ids.mapNotNull { albumDao.getById(it)?.toDomain() }
         }
 
     fun observeLikedTracks(): Flow<List<TrackRef>> =
-        likeDao.observeLikedIdsOfType(LOCAL_USER_ID, ENTITY_TRACK).map { ids ->
+        likeDao.observeLikedIdsOfType(currentUserId(), ENTITY_TRACK).map { ids ->
             ids.mapNotNull { trackDao.getById(it)?.toDomain() }
         }
 
     fun observeIsLiked(entityType: String, entityId: String): Flow<Boolean> =
-        likeDao.observeIsLiked(LOCAL_USER_ID, entityType, entityId)
+        likeDao.observeIsLiked(currentUserId(), entityType, entityId)
+
+    /**
+     * Reactive set of liked track ids. Use this when the caller only
+     * needs "is X in liked set", NOT when it needs to render the liked
+     * tracks themselves — [observeLikedTracks] does a `mapNotNull` join
+     * against `trackDao` and drops any liked id whose track isn't in
+     * local cache yet, so an "is liked" UI built on `observeLikedTracks`
+     * misses cross-device likes whose track row hasn't cached.
+     *
+     * Used by playlist/album detail screens to color a row's like
+     * button independent of whether the track is in the local library.
+     */
+    fun observeLikedTrackIds(): Flow<Set<String>> =
+        likeDao.observeLikedIdsOfType(currentUserId(), ENTITY_TRACK).map { it.toSet() }
 
     /** One-shot snapshot of the liked track-id set — for the offline pool filter. */
     suspend fun likedTrackIds(): Set<String> =
-        likeDao.observeLikedIdsOfType(LOCAL_USER_ID, ENTITY_TRACK).first().toSet()
+        likeDao.observeLikedIdsOfType(currentUserId(), ENTITY_TRACK).first().toSet()
 
     // ── Writes (optimistic local → best-effort REST → enqueue on fail) ──
 
@@ -85,13 +137,15 @@ class LikesRepository @Inject constructor(
      * if it got enqueued for later replay.
      */
     suspend fun toggleLike(entityType: String, entityId: String, desiredState: Boolean): Boolean {
-        // 1. Optimistic Room mutation.
+        // 1. Optimistic Room mutation — scoped to the signed-in user
+        //    (or the legacy "local" fallback for pre-#576 rows).
+        val uid = currentUserId()
         if (desiredState) {
             likeDao.upsertAll(
-                listOf(CachedLikeEntity(LOCAL_USER_ID, entityType, entityId)),
+                listOf(CachedLikeEntity(uid, entityType, entityId)),
             )
         } else {
-            likeDao.delete(LOCAL_USER_ID, entityType, entityId)
+            likeDao.delete(uid, entityType, entityId)
         }
         // 2. Best-effort REST call; 3. enqueue on failure.
         val kindPath = serverPathFor(entityType)
@@ -111,24 +165,38 @@ class LikesRepository @Inject constructor(
     }
 
     /**
-     * Pulls `GET /api/likes/ids` and reconciles `cached_likes`. Called
-     * by the LikedTab ViewModel on init (and by the SyncController in
-     * Phase 12). Adds rows for IDs the server has but we don't; the
-     * delete-of-stale-rows pass lives in the SyncController where the
-     * full reconciliation runs.
+     * Pulls `GET /api/likes/ids` and atomically replaces the user's
+     * cached_likes set with the server's canonical view. Called by
+     * the LikedTab ViewModel on init (and by the SyncController in
+     * Phase 12).
+     *
+     * Drift #570 fix: previously this called `upsertAll` only, which
+     * added rows for IDs the server had but never removed rows the
+     * server no longer surfaced — so a cross-device unlike (user
+     * likes on web, then unlikes on web) left the Liked tab on
+     * Android showing the now-unliked entry forever. The atomic
+     * replaceAllForUser DAO method runs a transactional delete-then-
+     * insert so the local set is exactly what the server reports.
      */
     suspend fun refreshIds() {
+        val uid = currentUserId()
         val wire = api.ids()
         val rows = mutableListOf<CachedLikeEntity>()
-        rows += wire.artistIds.map { CachedLikeEntity(LOCAL_USER_ID, ENTITY_ARTIST, it) }
-        rows += wire.albumIds.map { CachedLikeEntity(LOCAL_USER_ID, ENTITY_ALBUM, it) }
-        rows += wire.trackIds.map { CachedLikeEntity(LOCAL_USER_ID, ENTITY_TRACK, it) }
-        likeDao.upsertAll(rows)
+        rows += wire.artistIds.map { CachedLikeEntity(uid, ENTITY_ARTIST, it) }
+        rows += wire.albumIds.map { CachedLikeEntity(uid, ENTITY_ALBUM, it) }
+        rows += wire.trackIds.map { CachedLikeEntity(uid, ENTITY_TRACK, it) }
+        likeDao.replaceAllForUser(uid, rows)
     }
 
     companion object {
-        // TODO(Phase 11): swap for AuthStore.userId.value once auth lands.
-        const val LOCAL_USER_ID: String = "local"
+        // Pre-auth fallback discriminator. Drift #576: when no user is
+        // signed in OR for cached_likes rows written by pre-#576
+        // builds (which all tagged "local"), reads continue to query
+        // this bucket so the Liked tab isn't suddenly empty after the
+        // upgrade. The first authenticated refreshIds() call writes
+        // rows under the real user UUID; reads then transparently
+        // switch over via currentUserId().
+        const val ANONYMOUS_USER_ID: String = "local"
         const val ENTITY_ARTIST: String = "artist"
         const val ENTITY_ALBUM: String = "album"
         const val ENTITY_TRACK: String = "track"

android/app/src/main/java/com/fabledsword/minstrel/models/Playlist.kt

@@ -20,6 +20,8 @@ data class PlaylistRef(
     val trackCount: Int = 0,
     val coverUrl: String = "",
     val ownerUsername: String = "",
+    /** All member tracks resident in the audio cache — playable fully offline. */
+    val fullyCached: Boolean = false,
 ) {
     val isSystem: Boolean get() = systemVariant != null
 
@@ -30,6 +32,13 @@ data class PlaylistRef(
      * expose a refresh trigger; rebuilds are scheduler-driven).
      */
     val refreshable: Boolean get() = isSystem && systemVariant != "songs_like_artist"
+
+    /**
+     * Can't be relied on while offline — either it needs the live server to
+     * (re)generate (a refreshable system mix) or not all its tracks are cached.
+     * Callers combine this with the current offline state to grey the tile.
+     */
+    val unavailableOffline: Boolean get() = refreshable || !fullyCached
 }
 
 /**

android/app/src/main/java/com/fabledsword/minstrel/models/wire/EventsWire.kt

@@ -1,5 +1,9 @@
+@file:OptIn(ExperimentalSerializationApi::class)
+
 package com.fabledsword.minstrel.models.wire
 
+import kotlinx.serialization.EncodeDefault
+import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 
@@ -15,7 +19,11 @@ import kotlinx.serialization.Serializable
 
 @Serializable
 data class PlayStartedRequest(
-    val type: String = "play_started",
+    // Discriminator MUST stay on the wire. The app's Json has
+    // encodeDefaults=false, so without this a `type` left at its
+    // default is omitted entirely and the server 400s the event as
+    // "unknown event type" — silently dropping every native play.
+    @EncodeDefault(EncodeDefault.Mode.ALWAYS) val type: String = "play_started",
     @SerialName("track_id") val trackId: String,
     @SerialName("client_id") val clientId: String,
     val source: String? = null,
@@ -28,21 +36,21 @@ data class PlayStartedResponse(
 
 @Serializable
 data class PlayEndedRequest(
-    val type: String = "play_ended",
+    @EncodeDefault(EncodeDefault.Mode.ALWAYS) val type: String = "play_ended",
     @SerialName("play_event_id") val playEventId: String,
     @SerialName("duration_played_ms") val durationPlayedMs: Long,
 )
 
 @Serializable
 data class PlaySkippedRequest(
-    val type: String = "play_skipped",
+    @EncodeDefault(EncodeDefault.Mode.ALWAYS) val type: String = "play_skipped",
     @SerialName("play_event_id") val playEventId: String,
     @SerialName("position_ms") val positionMs: Long,
 )
 
 @Serializable
 data class PlayOfflineRequest(
-    val type: String = "play_offline",
+    @EncodeDefault(EncodeDefault.Mode.ALWAYS) val type: String = "play_offline",
     @SerialName("track_id") val trackId: String,
     @SerialName("client_id") val clientId: String,
     val at: String,

android/app/src/main/java/com/fabledsword/minstrel/models/wire/HomeIndexWire.kt

@@ -10,13 +10,17 @@ import kotlinx.serialization.Serializable
  * `internal/api/types.go HomeIndexPayload`).
  *
  * Section name implies entity type; no per-entry type tag is needed:
- *   - recentlyAddedAlbums → album
- *   - rediscoverAlbums    → album
- *   - rediscoverArtists   → artist
- *   - mostPlayedTracks    → track
- *   - lastPlayedArtists   → artist
+ *   - recentlyAddedAlbums  → album
+ *   - rediscoverAlbums     → album
+ *   - rediscoverArtists    → artist
+ *   - mostPlayedTracks     → track
+ *   - lastPlayedArtists    → artist
+ *   - youMightLikeAlbums   → album
+ *   - youMightLikeArtists  → artist
  *
- * All slices default to empty so missing keys don't throw on decode.
+ * All slices default to empty so missing keys don't throw on decode —
+ * which also keeps the client safe against older servers that don't
+ * emit the you-might-like sections yet.
  */
 @Serializable
 data class HomeIndexWire(
@@ -25,4 +29,6 @@ data class HomeIndexWire(
     @SerialName("rediscover_artists") val rediscoverArtists: List<String> = emptyList(),
     @SerialName("most_played_tracks") val mostPlayedTracks: List<String> = emptyList(),
     @SerialName("last_played_artists") val lastPlayedArtists: List<String> = emptyList(),
+    @SerialName("you_might_like_albums") val youMightLikeAlbums: List<String> = emptyList(),
+    @SerialName("you_might_like_artists") val youMightLikeArtists: List<String> = emptyList(),
 )

android/app/src/main/java/com/fabledsword/minstrel/player/AudioPrefetcher.kt

@@ -58,59 +58,98 @@ class AudioPrefetcher @Inject constructor(
     private val activeJobs = mutableMapOf<String, Job>()
     private val mutex = Mutex()
 
+    private data class ReconcileInput(
+        val queue: List<Pair<String, String>>,
+        val index: Int,
+        val window: Int,
+        val isPlaying: Boolean,
+    )
+
     init {
         scope.launch {
             combine(
                 playerController.uiState.map { it.queue.map { t -> t.id to t.streamUrl } },
                 playerController.uiState.map { it.queueIndex },
                 authStore.cacheSettings.map { it.prefetchWindow },
-            ) { queue, index, window -> Triple(queue, index, window) }
+                playerController.uiState.map { it.isPlaying },
+            ) { queue, index, window, isPlaying ->
+                ReconcileInput(queue, index, window, isPlaying)
+            }
                 .distinctUntilChanged()
-                .collect { (queue, index, window) -> reconcile(queue, index, window) }
+                .collect { input ->
+                    reconcile(input.queue, input.index, input.window, input.isPlaying)
+                }
         }
     }
 
+    /**
+     * Apply the prefetch window to the current queue.
+     *
+     * Cancellation of out-of-window jobs always runs -- a queue mutation
+     * or skip should free bandwidth from stale prefetches immediately.
+     * Starting new prefetches is gated on [isPlaying]: until the current
+     * track is actually playing, every byte of upstream bandwidth should
+     * land on it, not on upcoming-track prefetches. Without this gate a
+     * cold start fanned out 4-6 concurrent CacheWriter jobs against the
+     * same OkHttp client as the playback DataSource and the user waited
+     * ~25 s for the first audio to start; with the gate the current
+     * track gets the full pipe to its first STATE_READY, then the
+     * prefetcher fills in the next window.
+     */
     private suspend fun reconcile(
         queue: List<Pair<String, String>>,
         index: Int,
         window: Int,
+        isPlaying: Boolean,
     ) {
         mutex.withLock {
-            if (index < 0 || queue.isEmpty() || window <= 0) {
+            val targets = computeTargets(queue, index, window)
+            if (targets.isEmpty()) {
                 cancelAllLocked()
                 return
             }
-            // Exclude the currently-playing track (it's loaded by the
-            // player itself) and walk `window` tracks forward.
-            val firstIdx = (index + 1).coerceAtMost(queue.size)
-            val lastIdx = (index + window).coerceAtMost(queue.size - 1)
-            if (firstIdx > lastIdx) {
-                cancelAllLocked()
-                return
-            }
-            val targets = queue.subList(firstIdx, lastIdx + 1)
             val targetIds = targets.mapTo(mutableSetOf()) { it.first }
+            // Cancellation always runs so a queue mutation or skip frees
+            // the pipe immediately, even while paused.
+            cancelOutOfWindowLocked(targetIds)
+            if (isPlaying) startInWindowLocked(targets)
+        }
+    }
 
-            // Cancel jobs for tracks that have slid out of the window.
-            activeJobs.entries
-                .filter { it.key !in targetIds }
-                .toList()
-                .forEach { (id, job) ->
-                    job.cancel()
-                    activeJobs.remove(id)
-                }
+    private fun computeTargets(
+        queue: List<Pair<String, String>>,
+        index: Int,
+        window: Int,
+    ): List<Pair<String, String>> {
+        // Exclude the currently-playing track (it's loaded by the player
+        // itself) and walk `window` tracks forward.
+        val firstIdx = index + 1
+        val lastIdx = (index + window).coerceAtMost(queue.size - 1)
+        val isValid = index >= 0 && queue.isNotEmpty() && window > 0 && firstIdx <= lastIdx
+        return if (isValid) queue.subList(firstIdx, lastIdx + 1) else emptyList()
+    }
 
-            // Start prefetches for new arrivals. Skip blank URLs (these
-            // come from minimal TrackRefs synthesized from playlist rows
-            // when the upstream track was removed from the library).
-            for ((trackId, streamUrl) in targets) {
-                if (trackId in activeJobs || streamUrl.isBlank()) continue
-                val job = scope.launch(Dispatchers.IO) {
-                    runCatching { prefetchOne(trackId, streamUrl) }
-                    mutex.withLock { activeJobs.remove(trackId) }
-                }
-                activeJobs[trackId] = job
+    private fun cancelOutOfWindowLocked(targetIds: Set<String>) {
+        activeJobs.entries
+            .filter { it.key !in targetIds }
+            .toList()
+            .forEach { (id, job) ->
+                job.cancel()
+                activeJobs.remove(id)
             }
+    }
+
+    private fun startInWindowLocked(targets: List<Pair<String, String>>) {
+        // Skip blank URLs (these come from minimal TrackRefs synthesized
+        // from playlist rows when the upstream track was removed from
+        // the library).
+        for ((trackId, streamUrl) in targets) {
+            if (trackId in activeJobs || streamUrl.isBlank()) continue
+            val job = scope.launch(Dispatchers.IO) {
+                runCatching { prefetchOne(trackId, streamUrl) }
+                mutex.withLock { activeJobs.remove(trackId) }
+            }
+            activeJobs[trackId] = job
         }
     }
 

android/app/src/main/java/com/fabledsword/minstrel/player/LikeMediaCallback.kt

@@ -0,0 +1,78 @@
+package com.fabledsword.minstrel.player
+
+import android.os.Bundle
+import androidx.media3.session.MediaSession
+import androidx.media3.session.SessionCommand
+import androidx.media3.session.SessionResult
+import com.fabledsword.minstrel.likes.data.LikesRepository
+import com.fabledsword.minstrel.likes.data.LikesRepository.Companion.ENTITY_TRACK
+import com.google.common.util.concurrent.Futures
+import com.google.common.util.concurrent.ListenableFuture
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.launch
+
+/**
+ * MediaSession callback that adds the like/heart custom command to
+ * every connecting controller (notification, lock screen, Pixel Watch,
+ * Android Auto) and routes taps through [LikesRepository.toggleLike]
+ * so they inherit the offline-resilient MutationQueue path.
+ *
+ * The [onConnect] grant is REQUIRED — without it the button is
+ * silently invisible on some surfaces (Media3 issue #2679). See the
+ * spec at docs/superpowers/specs/2026-06-02-android-media3-like-button-design.md.
+ *
+ * Suspend work in [onCustomCommand] is launched on [scope] (a
+ * service-lifetime scope) so the callback returns synchronously and
+ * the controller does not block on Room + REST. State updates flow
+ * back through [LikesRepository.observeIsLiked] so the icon refreshes
+ * via the like-state job in [MinstrelPlayerService].
+ */
+class LikeMediaCallback(
+    private val likes: LikesRepository,
+    private val scope: CoroutineScope,
+) : MediaSession.Callback {
+
+    override fun onConnect(
+        session: MediaSession,
+        controller: MediaSession.ControllerInfo,
+    ): MediaSession.ConnectionResult {
+        val grants = MediaSession.ConnectionResult.DEFAULT_SESSION_COMMANDS
+            .buildUpon()
+            .add(SessionCommand(CMD_TOGGLE_LIKE, Bundle.EMPTY))
+            .build()
+        return MediaSession.ConnectionResult.AcceptedResultBuilder(session)
+            .setAvailableSessionCommands(grants)
+            .build()
+    }
+
+    override fun onCustomCommand(
+        session: MediaSession,
+        controller: MediaSession.ControllerInfo,
+        customCommand: SessionCommand,
+        args: Bundle,
+    ): ListenableFuture<SessionResult> {
+        val code = if (customCommand.customAction == CMD_TOGGLE_LIKE) {
+            launchToggleForCurrent(session)
+        } else {
+            SessionResult.RESULT_ERROR_NOT_SUPPORTED
+        }
+        return Futures.immediateFuture(SessionResult(code))
+    }
+
+    private fun launchToggleForCurrent(session: MediaSession): Int {
+        val mediaId = session.player.currentMediaItem?.mediaId
+            ?: return SessionResult.RESULT_INFO_SKIPPED
+        scope.launch {
+            val current = likes.observeIsLiked(ENTITY_TRACK, mediaId).first()
+            likes.toggleLike(ENTITY_TRACK, mediaId, !current)
+        }
+        return SessionResult.RESULT_SUCCESS
+    }
+
+    companion object {
+        /** Custom-action key for the like/heart button. Namespaced so
+         *  future custom commands (output picker, etc.) don't collide. */
+        const val CMD_TOGGLE_LIKE: String = "minstrel.toggle_like"
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/MinstrelForwardingPlayer.kt

@@ -0,0 +1,587 @@
+@file:Suppress("TooManyFunctions") // Mirrors Player surface: ~16 methods is the API.
+
+package com.fabledsword.minstrel.player
+
+import android.os.Handler
+import android.os.SystemClock
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.ProcessLifecycleOwner
+import androidx.media3.common.ForwardingPlayer
+import androidx.media3.common.MediaItem
+import androidx.media3.common.Player
+import com.fabledsword.minstrel.player.output.ActiveUpnp
+import com.fabledsword.minstrel.player.output.ActiveUpnpHolder
+import com.fabledsword.minstrel.player.output.upnp.SoapFaultException
+import com.fabledsword.minstrel.player.output.upnp.TransportState
+import java.io.IOException
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.selects.onTimeout
+import kotlinx.coroutines.selects.select
+import timber.log.Timber
+
+/**
+ * Integration point for UPnP transport parity. Wraps the local
+ * ExoPlayer; every transport method either forwards (local route
+ * active -- the default) or translates into AVTransport SOAP +
+ * [RemotePlayerState] updates (UPnP route active).
+ *
+ * Created inside [MinstrelPlayerService]; runs on the service's main
+ * looper. Network SOAP calls fire on [Dispatchers.IO]. While UPnP is
+ * active, the MediaSession's reads of [Player.isPlaying] and
+ * [Player.getCurrentPosition] pull from [RemotePlayerState]; the
+ * wrapped ExoPlayer stays paused at the position it had when the
+ * route was selected.
+ *
+ * Drop heuristic: the 1 Hz poll loop is the *sole* arbiter of route
+ * liveness -- [RemotePlayerState.recordPollFailure]'s rolling threshold
+ * (DROP_THRESHOLD consecutive failures) fires [onDrop]. A failed transport
+ * command (play/pause/seek/next) does NOT drop on its own: a locked phone's
+ * WiFi power-save can stall a single command's socket I/O for a second or
+ * two while the renderer is perfectly reachable, so commands retry on
+ * transient IO failure and otherwise defer to the poll loop. The factory
+ * wraps the [onDrop] callback into a SharedFlow consumed by the NowPlaying
+ * surface as a snackbar.
+ *
+ * Queue mode: OutputPickerController loads the full queue into Sonos's
+ * native queue via ClearQueue + AddURIToQueue, then points the
+ * transport at x-rincon-queue:<udn>#0. Skip/prev/seekTo delegate to
+ * AVTransport Next/Previous/SeekToTrack so Sonos manages gap-free
+ * advance natively. PollLoop syncs the local cursor by comparing the
+ * 1-based Track index from GetPositionInfo.
+ */
+class MinstrelForwardingPlayer(
+    private val delegate: Player,
+    private val holder: ActiveUpnpHolder,
+    private val remoteState: RemotePlayerState,
+    private val onDrop: (routeName: String) -> Unit,
+) : ForwardingPlayer(delegate) {
+
+    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.IO)
+    private val handler = Handler(delegate.applicationLooper)
+    private var pollJob: Job? = null
+
+    // Tracks consecutive non-PLAYING poll observations so a single transient
+    // PAUSED_PLAYBACK / STOPPED tick during a Sonos track transition does not
+    // flip the play/pause button. Manual pause still feels instant because it
+    // bypasses the poll entirely via applyTransportPaused().
+    @Volatile private var nonPlayingPollStreak = 0
+
+    // Wall-clock of the most-recent within-track seek we issued to Sonos.
+    // pollOnce uses this to suppress position overwrites for SEEK_ACK_WINDOW_MS
+    // -- Sonos can take 1-2s to apply a Seek, and a poll landing inside that
+    // window reports the *old* position. Without the lockout the scrubber
+    // visibly jumps backwards immediately after a drag, then forwards again.
+    @Volatile private var lastSeekIssuedAtMs: Long = 0L
+
+    // Wake channel for the poll loop. requestImmediatePoll() trySend's a Unit;
+    // pollLoop's select{} races the delay against this channel so the next
+    // pollOnce can fire immediately instead of waiting up to POLL_INTERVAL_MS.
+    // Used on activity resume (ProcessLifecycleOwner.ON_RESUME) so the UI
+    // catches up to Sonos within RTT rather than the full poll cadence.
+    // CONFLATED so repeated trySend's between polls don't queue up.
+    private val pollTrigger = Channel<Unit>(Channel.CONFLATED)
+
+    // External Player.Listener registry (separate from super.addListener which
+    // forwards to the wrapped ExoPlayer). The wrapped player is paused with
+    // no audio loaded while UPnP is active, so it never fires events for our
+    // synthesized remote state -- the MediaSession's notification card and
+    // lock-screen scrubber stay frozen on whatever state was last captured
+    // before UPnP took over. We dual-register: super.addListener keeps the
+    // listener attached to the delegate (so local-playback events still
+    // reach it), AND we hold a ref here so we can directly invoke listener
+    // callbacks on remote-state changes. The listener's read of isPlaying /
+    // duration / position then routes through our overrides to remoteState.
+    private val externalListeners = mutableListOf<Player.Listener>()
+
+    @Volatile private var lastNotifiedIsPlaying: Boolean = false
+    @Volatile private var lastNotifiedTrackIdx: Int = -1
+
+    private val lifecycleObserver = object : DefaultLifecycleObserver {
+        override fun onResume(owner: LifecycleOwner) {
+            pollTrigger.trySend(Unit)
+        }
+    }
+
+    init {
+        scope.launch {
+            holder.active.collect { active -> onActiveChanged(active) }
+        }
+        // Process lifecycle is observed on the main thread; ProcessLifecycleOwner's
+        // addObserver requires it. The observer just trySend's to the channel.
+        handler.post {
+            ProcessLifecycleOwner.get().lifecycle.addObserver(lifecycleObserver)
+        }
+    }
+
+    private fun isRemote(): Boolean = holder.active.value != null
+
+    /**
+     * Returns true when selectUpnp has marked a UPnP route as the intended
+     * target but loadQueueOnSonos hasn't yet wired ActiveUpnp. During this
+     * window we drop transport commands silently -- they would hit Sonos's
+     * stale state from a prior session and trigger restarts.
+     */
+    private fun isLoadingUpnp(): Boolean =
+        holder.target.value != null && holder.active.value == null
+
+    // ─── setMediaItems intercepts ──────────────────────────────────────
+    // When PlayerController.setQueue replaces the queue while Sonos is the
+    // active route, the wrapped delegate's queue gets the new items but
+    // Sonos's native queue still holds the OLD tracks -- and the play()
+    // that PlayerController fires immediately after setMediaItems would
+    // resume the old Sonos queue (user reported on-device: "player view
+    // updates but Sonos queue does not"). We clear active + set target
+    // synchronously here so the next play() in the same IPC sequence
+    // drops via isLoadingUpnp() = true; the OutputPickerController
+    // observes the uiState.queue change and runs the resync (re-clears
+    // Sonos's native queue + AddURIToQueue the new tracks + Play).
+
+    override fun setMediaItems(mediaItems: List<MediaItem>) {
+        super.setMediaItems(mediaItems)
+        markPendingResyncIfRemote()
+    }
+
+    override fun setMediaItems(mediaItems: List<MediaItem>, resetPosition: Boolean) {
+        super.setMediaItems(mediaItems, resetPosition)
+        markPendingResyncIfRemote()
+    }
+
+    override fun setMediaItems(mediaItems: List<MediaItem>, startIndex: Int, startPositionMs: Long) {
+        super.setMediaItems(mediaItems, startIndex, startPositionMs)
+        markPendingResyncIfRemote()
+    }
+
+    private fun markPendingResyncIfRemote() {
+        val wasActive = holder.active.value ?: return
+        Timber.w(
+            "setMediaItems while UPnP active (%s) -- marking pending resync",
+            wasActive.routeName,
+        )
+        holder.set(null)
+        holder.setTarget(wasActive.routeId)
+    }
+
+    override fun play() {
+        if (isLoadingUpnp()) {
+            Timber.w("ForwardingPlayer.play() dropped -- UPnP loading")
+            return
+        }
+        val active = holder.active.value
+        Timber.w("ForwardingPlayer.play() active=%s", active?.routeName)
+        if (active == null) {
+            super.play()
+        } else {
+            remoteState.setPlayIntent(true)
+            scope.launch {
+                runCatching { retryTransport { active.avTransport.play() } }
+                    .onSuccess {
+                        remoteState.applyTransportPlaying()
+                        notifyRemoteStateChanged()
+                    }
+                    .onFailure { handleTransportFailure(active, it) }
+            }
+        }
+    }
+
+    override fun pause() {
+        if (isLoadingUpnp()) {
+            Timber.w("ForwardingPlayer.pause() dropped -- UPnP loading")
+            return
+        }
+        val active = holder.active.value
+        Timber.w("ForwardingPlayer.pause() active=%s", active?.routeName)
+        if (active == null) {
+            super.pause()
+        } else {
+            remoteState.setPlayIntent(false)
+            scope.launch {
+                runCatching { retryTransport { active.avTransport.pause() } }
+                    .onSuccess {
+                        remoteState.applyTransportPaused()
+                        notifyRemoteStateChanged()
+                    }
+                    .onFailure { handleTransportFailure(active, it) }
+            }
+        }
+    }
+
+    override fun seekTo(positionMs: Long) {
+        if (isLoadingUpnp()) {
+            Timber.w("ForwardingPlayer.seekTo(positionMs) dropped -- UPnP loading")
+            return
+        }
+        val active = holder.active.value
+        Timber.w("ForwardingPlayer.seekTo(%dms) active=%s", positionMs, active?.routeName)
+        if (active == null) {
+            super.seekTo(positionMs)
+        } else {
+            lastSeekIssuedAtMs = SystemClock.elapsedRealtime()
+            remoteState.applyPositionInfo(
+                positionMs = positionMs,
+                durationMs = remoteState.durationMs,
+                trackUri = remoteState.currentTrackUri,
+                trackNumber = remoteState.trackNumber,
+            )
+            scope.launch {
+                runCatching { retryTransport { active.avTransport.seek(positionMs) } }
+                    .onFailure { handleTransportFailure(active, it) }
+            }
+        }
+    }
+
+    /**
+     * Widget-driven track change (user taps a track in the queue widget).
+     * Seeks Sonos to the correct queue slot, then seeks within-track if
+     * [positionMs] is non-zero.
+     */
+    override fun seekTo(mediaItemIndex: Int, positionMs: Long) {
+        if (isLoadingUpnp()) {
+            Timber.w("ForwardingPlayer.seekTo(idx, positionMs) dropped -- UPnP loading")
+            return
+        }
+        val active = holder.active.value
+        Timber.w(
+            "ForwardingPlayer.seekTo(idx=%d, %dms) active=%s",
+            mediaItemIndex, positionMs, active?.routeName,
+        )
+        if (active == null) {
+            super.seekTo(mediaItemIndex, positionMs)
+            return
+        }
+        super.seekTo(mediaItemIndex, positionMs)
+        remoteState.beginPendingTransport(
+            SystemClock.elapsedRealtime() + PENDING_TRANSPORT_SAFETY_TIMEOUT_MS,
+        )
+        scope.launch {
+            runCatching {
+                retryTransport {
+                    active.avTransport.seekToTrack(mediaItemIndex + 1)
+                    if (positionMs > 0L) {
+                        active.avTransport.seek(positionMs)
+                    }
+                }
+            }.onFailure { handleTransportFailure(active, it) }
+        }
+    }
+
+    override fun seekToNextMediaItem() {
+        if (isLoadingUpnp()) {
+            Timber.w("ForwardingPlayer.seekToNextMediaItem() dropped -- UPnP loading")
+            return
+        }
+        val active = holder.active.value
+        Timber.w("ForwardingPlayer.seekToNextMediaItem() active=%s", active?.routeName)
+        if (active == null) {
+            super.seekToNextMediaItem()
+            return
+        }
+        // Super first for immediate local cursor advance (UI feedback);
+        // then delegate to Sonos Next. PollLoop reconciles cursor via
+        // Track index if they diverge.
+        super.seekToNextMediaItem()
+        remoteState.beginPendingTransport(
+            SystemClock.elapsedRealtime() + PENDING_TRANSPORT_SAFETY_TIMEOUT_MS,
+        )
+        scope.launch {
+            runCatching { retryTransport { active.avTransport.next() } }
+                .onFailure { handleTransportFailure(active, it) }
+        }
+    }
+
+    override fun seekToPreviousMediaItem() {
+        if (isLoadingUpnp()) {
+            Timber.w("ForwardingPlayer.seekToPreviousMediaItem() dropped -- UPnP loading")
+            return
+        }
+        val active = holder.active.value
+        Timber.w("ForwardingPlayer.seekToPreviousMediaItem() active=%s", active?.routeName)
+        if (active == null) {
+            super.seekToPreviousMediaItem()
+            return
+        }
+        // Super first for immediate local cursor advance (UI feedback);
+        // then delegate to Sonos Previous. PollLoop reconciles.
+        super.seekToPreviousMediaItem()
+        remoteState.beginPendingTransport(
+            SystemClock.elapsedRealtime() + PENDING_TRANSPORT_SAFETY_TIMEOUT_MS,
+        )
+        scope.launch {
+            runCatching { retryTransport { active.avTransport.previous() } }
+                .onFailure { handleTransportFailure(active, it) }
+        }
+    }
+
+    override fun getCurrentPosition(): Long =
+        if (isRemote()) remoteState.positionMs else super.getCurrentPosition()
+
+    override fun getDuration(): Long =
+        if (isRemote()) remoteState.durationMs else super.getDuration()
+
+    override fun isPlaying(): Boolean =
+        if (isRemote()) remoteState.isPlaying else super.isPlaying()
+
+    override fun getPlaybackState(): Int =
+        if (isRemote()) Player.STATE_READY else super.getPlaybackState()
+
+    // Mirror remote state so any consumer that gates on playWhenReady --
+    // notably MediaSessionService's foreground-keepalive checks and our own
+    // onTaskRemoved -- sees the remote renderer as the source of truth.
+    // Without this, swiping the app away with Sonos playing would stop the
+    // service, kill the poll loop, and leave Sonos orphaned.
+    override fun getPlayWhenReady(): Boolean =
+        if (isRemote()) remoteState.isPlaying else super.getPlayWhenReady()
+
+    override fun addListener(listener: Player.Listener) {
+        super.addListener(listener)
+        synchronized(externalListeners) { externalListeners.add(listener) }
+    }
+
+    override fun removeListener(listener: Player.Listener) {
+        super.removeListener(listener)
+        synchronized(externalListeners) { externalListeners.remove(listener) }
+    }
+
+    /**
+     * Direct-invoke the externally-registered Player.Listeners so the
+     * MediaSession's PlaybackState publisher (notification card, lock-screen
+     * scrubber, BT/AVRCP, Auto, Wear OS tile) re-reads our overridden state.
+     * The listeners then query isPlaying / getDuration / getCurrentPosition,
+     * all of which route through to remoteState while UPnP is active.
+     *
+     * Posted to the player's application looper because Player.Listener
+     * callbacks contract on the application thread.
+     */
+    private fun notifyRemoteStateChanged() {
+        if (!isRemote()) return
+        val playing = remoteState.isPlaying
+        val trackIdx = (remoteState.trackNumber - 1).coerceAtLeast(0)
+        val isPlayingChanged = playing != lastNotifiedIsPlaying
+        val trackChanged = trackIdx != lastNotifiedTrackIdx
+        if (!isPlayingChanged && !trackChanged) return
+        lastNotifiedIsPlaying = playing
+        lastNotifiedTrackIdx = trackIdx
+        val snapshot = synchronized(externalListeners) { externalListeners.toList() }
+        handler.post {
+            for (l in snapshot) {
+                if (isPlayingChanged) {
+                    l.onIsPlayingChanged(playing)
+                    l.onPlaybackStateChanged(Player.STATE_READY)
+                }
+                if (trackChanged) {
+                    val item = if (trackIdx < delegate.mediaItemCount) {
+                        delegate.getMediaItemAt(trackIdx)
+                    } else {
+                        null
+                    }
+                    l.onMediaItemTransition(item, Player.MEDIA_ITEM_TRANSITION_REASON_AUTO)
+                }
+            }
+        }
+    }
+
+    override fun release() {
+        pollJob?.cancel()
+        scope.cancel()
+        handler.post {
+            ProcessLifecycleOwner.get().lifecycle.removeObserver(lifecycleObserver)
+        }
+        super.release()
+    }
+
+    /**
+     * Run a transport SOAP block, retrying transport-level (IO) failures a
+     * few times with backoff. A locked phone's WiFi power-save can stall the
+     * first socket I/O for a second or two; a retry lets the command land once
+     * WiFi wakes instead of being abandoned. A [SoapFaultException] (the
+     * renderer answered and rejected the action) is NOT retried -- the device
+     * is alive and retrying won't change its verdict.
+     */
+    private suspend fun <T> retryTransport(block: suspend () -> T): T =
+        retryTransientIo(TRANSPORT_RETRY_ATTEMPTS, TRANSPORT_RETRY_BACKOFF_MS, block)
+
+    /**
+     * A transport SOAP command failed even after retries. Deliberately does
+     * NOT declare the route dropped: the 1 Hz poll loop is the single arbiter
+     * of liveness (DROP_THRESHOLD consecutive poll failures). A locked phone's
+     * WiFi power-save can fail one command while the renderer is perfectly
+     * reachable; dropping on a single command falsely kicked playback back to
+     * the phone. We log, leave the poll loop running, and nudge an immediate
+     * poll so the UI reconciles to Sonos's actual state -- if the renderer is
+     * truly gone, the poll loop trips the drop on its own.
+     */
+    private fun handleTransportFailure(active: ActiveUpnp, t: Throwable) {
+        if (t is SoapFaultException) {
+            Timber.w(t, "UPnP transport rejected by %s -- device alive, no drop", active.routeName)
+        } else {
+            Timber.w(t, "UPnP transport failed on %s -- poll loop arbitrates", active.routeName)
+        }
+        pollTrigger.trySend(Unit)
+    }
+
+    private fun onActiveChanged(active: ActiveUpnp?) {
+        pollJob?.cancel()
+        nonPlayingPollStreak = 0
+        // Reset notify cache so the first poll after a route flip republishes
+        // playing/track state to the MediaSession even if it happens to match
+        // the prior session's values numerically.
+        lastNotifiedIsPlaying = false
+        lastNotifiedTrackIdx = -1
+        if (active != null) {
+            Timber.w("UPnP active: %s -- pollLoop starting", active.routeName)
+            // Pause the wrapped ExoPlayer so we are not playing local audio
+            // simultaneously with the remote renderer. handler.post targets the
+            // application looper, so this runs on the same thread that processes
+            // our override calls -- no race with the pause() override branching
+            // to SOAP (holder.active is already non-null by the time this post
+            // fires, but delegate.pause() bypasses the override entirely).
+            handler.post { delegate.pause() }
+            pollJob = scope.launch { pollLoop(active) }
+        } else {
+            remoteState.reset()
+        }
+    }
+
+    @OptIn(ExperimentalCoroutinesApi::class) // onTimeout / select.onReceive
+    private suspend fun pollLoop(active: ActiveUpnp) {
+        while (scope.isActive && holder.active.value?.routeId == active.routeId) {
+            val outcome = runCatching { pollOnce(active) }
+            if (outcome.isSuccess) {
+                remoteState.recordPollSuccess()
+            } else if (remoteState.recordPollFailure()) {
+                Timber.w("UPnP drop threshold tripped for %s", active.routeName)
+                handler.post { onDrop(active.routeName) }
+                return
+            }
+            // Race the normal cadence against any external wake (activity
+            // resume). Whichever wins continues to the next pollOnce.
+            select<Unit> {
+                onTimeout(POLL_INTERVAL_MS) {}
+                pollTrigger.onReceive {}
+            }
+        }
+    }
+
+    /**
+     * One poll tick: read position + transport state from Sonos, apply to
+     * [remoteState], and forward-sync the local cursor to Sonos's Track
+     * index when not in queue load.
+     *
+     * Cursor sync is gated on `holder.target == null` (= not loading)
+     * because during load Sonos reports Track=1 while we're still
+     * appending, and syncing would race the SetAV+Seek that lands
+     * after. Outside load, forward sync catches Sonos auto-advances
+     * (queue end-of-track), Sonos-app driven Next presses, and any
+     * drift after a brief poll-failure burst that didn't trip the
+     * drop threshold. Forward-only because a Next override we just
+     * issued can race with a poll still reporting the prior Track --
+     * the next poll catches up safely.
+     */
+    private suspend fun pollOnce(active: ActiveUpnp) {
+        val info = active.avTransport.getPositionInfo()
+        val now = SystemClock.elapsedRealtime()
+        val inSeekAckWindow = lastSeekIssuedAtMs > 0L &&
+            (now - lastSeekIssuedAtMs) < SEEK_ACK_WINDOW_MS
+        // Inside the seek-ack window, keep the optimistic position we wrote in
+        // seekTo -- the poll's reported position is stale until Sonos finishes
+        // processing the Seek SOAP. Other fields still refresh from the poll.
+        remoteState.applyPositionInfo(
+            positionMs = if (inSeekAckWindow) remoteState.positionMs else info.relTimeMs,
+            durationMs = info.trackDurationMs,
+            trackUri = info.trackUri,
+            trackNumber = info.track,
+        )
+        maybeSyncLocalCursor(info.track)
+        val transport = active.avTransport.getTransportInfo()
+        when (transport.state) {
+            TransportState.PLAYING -> {
+                nonPlayingPollStreak = 0
+                remoteState.applyTransportPlaying()
+            }
+            TransportState.PAUSED -> {
+                nonPlayingPollStreak += 1
+                if (nonPlayingPollStreak >= NON_PLAYING_CONFIRM) {
+                    remoteState.applyTransportPaused()
+                }
+            }
+            TransportState.STOPPED -> {
+                nonPlayingPollStreak += 1
+                if (nonPlayingPollStreak >= NON_PLAYING_CONFIRM) {
+                    remoteState.applyTransportStopped()
+                }
+            }
+            TransportState.TRANSITIONING, TransportState.UNKNOWN -> Unit
+        }
+        notifyRemoteStateChanged()
+    }
+
+    private fun maybeSyncLocalCursor(sonosTrack: Int) {
+        if (holder.target.value != null) return
+        if (sonosTrack <= 0) return
+        val sonosIdx = sonosTrack - 1
+        handler.post {
+            val localIdx = delegate.currentMediaItemIndex
+            if (sonosIdx > localIdx && sonosIdx < delegate.mediaItemCount) {
+                Timber.w(
+                    "UPnP cursor catch-up: local=%d -> sonos=%d",
+                    localIdx, sonosIdx,
+                )
+                delegate.seekTo(sonosIdx, 0L)
+            }
+        }
+    }
+
+    private companion object {
+        const val POLL_INTERVAL_MS = 1_000L
+        const val NON_PLAYING_CONFIRM = 2
+        const val SEEK_ACK_WINDOW_MS = 2_000L
+        // Safety upper bound on how long the polling tick will wait for
+        // Sonos to ack a user transport. The common case clears event-driven
+        // when Sonos's reported Track matches the wrapped player; this only
+        // kicks in if SOAP fails or Sonos drops the ack entirely.
+        const val PENDING_TRANSPORT_SAFETY_TIMEOUT_MS = 5_000L
+        // Transport commands retry transient IO failures so a single WiFi
+        // power-save stall (locked phone) doesn't abandon the command. 3
+        // attempts x the SoapClient's 2s connect timeout + backoff bounds the
+        // worst case at ~7s; a still-failing command then defers to the poll.
+        const val TRANSPORT_RETRY_ATTEMPTS = 3
+        const val TRANSPORT_RETRY_BACKOFF_MS = 400L
+    }
+}
+
+/**
+ * Retry [block] on transient transport-level ([IOException]) failures, with
+ * [backoffMs] between attempts, up to [attempts] total. Anything that is not
+ * an [IOException] -- notably [SoapFaultException], where the renderer
+ * answered and rejected the action -- propagates immediately: the device is
+ * alive, so retrying won't change its verdict. Extracted from
+ * [MinstrelForwardingPlayer] so a locked phone's WiFi power-save stall doesn't
+ * abandon a single transport command (the bug that falsely reverted Sonos
+ * playback to local audio).
+ */
+internal suspend fun <T> retryTransientIo(
+    attempts: Int,
+    backoffMs: Long,
+    block: suspend () -> T,
+): T {
+    var attempt = 0
+    while (true) {
+        try {
+            return block()
+        } catch (io: IOException) {
+            attempt += 1
+            if (attempt >= attempts) throw io
+            Timber.w(io, "transient transport failure (attempt %d) -- retrying", attempt)
+            delay(backoffMs)
+        }
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/MinstrelPlayerService.kt

@@ -1,10 +1,30 @@
 package com.fabledsword.minstrel.player
 
+import android.app.PendingIntent
 import android.content.Intent
+import android.os.Bundle
+import androidx.media3.common.MediaItem
 import androidx.media3.common.Player
+import androidx.media3.session.CommandButton
 import androidx.media3.session.MediaSession
 import androidx.media3.session.MediaSessionService
+import androidx.media3.session.SessionCommand
+import com.fabledsword.minstrel.MainActivity
+import com.fabledsword.minstrel.likes.data.LikesRepository
+import com.fabledsword.minstrel.likes.data.LikesRepository.Companion.ENTITY_TRACK
+import com.google.common.collect.ImmutableList
 import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.channels.awaitClose
+import kotlinx.coroutines.flow.callbackFlow
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.flow.onStart
+import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 /**
@@ -18,35 +38,150 @@ import javax.inject.Inject
  * MediaButtonReceiver is registered automatically by the library, no
  * manual receiver class needed.
  *
+ * The session advertises a single custom CommandButton — the like/heart
+ * toggle. [LikeMediaCallback] grants the command in `onConnect` and
+ * routes taps through [LikesRepository.toggleLike] so they inherit the
+ * offline-resilient MutationQueue path. The icon mirrors server state:
+ * a service-scoped coroutine collects `currentMediaItem × isLiked` and
+ * rebuilds the preferences list on each emission so a cross-device
+ * like (web tap) flips the notification heart automatically.
+ *
  * Lifecycle:
- *   - onCreate: build the ExoPlayer + MediaSession once.
+ *   - onCreate: build the ExoPlayer + MediaSession once, attach the
+ *     callback, set initial preferences, launch the like-state job.
  *   - onGetSession: return the live session to any binding controller
  *     (system UI media card, Wear OS companion, MediaController3 clients).
  *   - onTaskRemoved: if the user swipes the app away, keep playing when
  *     audio is active (standard media-app behavior — music shouldn't
  *     die because the app left recents); otherwise stop the service so
  *     the lingering notification clears.
- *   - onDestroy: release the session + player.
+ *   - onDestroy: cancel the service scope, then release the session +
+ *     player. Cancellation comes first so the like-state job doesn't
+ *     touch a released session.
  */
 @AndroidEntryPoint
 class MinstrelPlayerService : MediaSessionService() {
 
     @Inject lateinit var playerFactory: PlayerFactory
 
+    @Inject lateinit var likesRepository: LikesRepository
+
+    private val serviceScope = CoroutineScope(SupervisorJob() + Dispatchers.Main.immediate)
+
     private var mediaSession: MediaSession? = null
 
     override fun onCreate() {
         super.onCreate()
-        val player = playerFactory.build()
-        mediaSession = MediaSession.Builder(this, player).build()
+        val player: Player = playerFactory.build()
+        val callback = LikeMediaCallback(likesRepository, serviceScope)
+        val session = MediaSession.Builder(this, player)
+            .setSessionActivity(buildNowPlayingPendingIntent())
+            .setCallback(callback)
+            .setBitmapLoader(playerFactory.buildBitmapLoader())
+            .setMediaButtonPreferences(ImmutableList.of(buildLikeButton(isLiked = false)))
+            .build()
+        mediaSession = session
+        serviceScope.launch { observeLikeState(session, player) }
     }
 
+    /**
+     * Intent that the media notification / lock-screen card / Pixel
+     * Watch tile launches when tapped. Carries an extra MainActivity
+     * consumes to navigate the NavController straight to the full
+     * NowPlaying screen — without it, Media3 defaults to the launcher
+     * activity entry point, which lands on whatever shell route
+     * MainActivity last rendered.
+     *
+     * FLAG_ACTIVITY_SINGLE_TOP keeps the existing MainActivity instance
+     * alive when one is already foregrounded; onNewIntent fires and
+     * picks up the fresh extra. FLAG_IMMUTABLE is required on
+     * Android 12+; FLAG_UPDATE_CURRENT keeps the extra in sync if the
+     * Builder rebuilds the PendingIntent.
+     */
+    private fun buildNowPlayingPendingIntent(): PendingIntent {
+        val intent = Intent(this, MainActivity::class.java).apply {
+            flags = Intent.FLAG_ACTIVITY_SINGLE_TOP
+            putExtra(MainActivity.EXTRA_OPEN_NOW_PLAYING, true)
+        }
+        return PendingIntent.getActivity(
+            this,
+            REQUEST_OPEN_NOW_PLAYING,
+            intent,
+            PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT,
+        )
+    }
+
+    /**
+     * Build the like/heart CommandButton. Icon flips between
+     * ICON_HEART_FILLED and ICON_HEART_UNFILLED to mirror server-side
+     * like state. The session command is the same in both states so
+     * the callback's onCustomCommand handles them identically (it
+     * inverts the current observed state regardless of which icon was
+     * tapped).
+     */
+    private fun buildLikeButton(isLiked: Boolean): CommandButton {
+        val icon = if (isLiked) {
+            CommandButton.ICON_HEART_FILLED
+        } else {
+            CommandButton.ICON_HEART_UNFILLED
+        }
+        return CommandButton.Builder(icon)
+            .setDisplayName(if (isLiked) "Unlike" else "Like")
+            .setSessionCommand(SessionCommand(LikeMediaCallback.CMD_TOGGLE_LIKE, Bundle.EMPTY))
+            .build()
+    }
+
+    /**
+     * Collect player.currentMediaItem changes (via a Player.Listener
+     * lifted into a Flow) and, for each non-null mediaId, observe its
+     * liked state. On every emission, rebuild the session's media
+     * button preferences with the icon flipped accordingly.
+     * flatMapLatest cancels the previous track's subscription so we
+     * never leak Flows across track transitions.
+     */
+    @OptIn(ExperimentalCoroutinesApi::class)
+    private suspend fun observeLikeState(session: MediaSession, player: Player) {
+        currentMediaIdFlow(player)
+            .flatMapLatest { mediaId ->
+                if (mediaId == null) {
+                    flowOf(false)
+                } else {
+                    likesRepository.observeIsLiked(ENTITY_TRACK, mediaId)
+                }
+            }
+            .collect { isLiked ->
+                session.setMediaButtonPreferences(
+                    ImmutableList.of(buildLikeButton(isLiked = isLiked)),
+                )
+            }
+    }
+
+    /**
+     * Lift Player.currentMediaItem changes into a Flow. Emits the
+     * current mediaId on subscription so the initial icon state is
+     * correct on the first frame the controller renders (no
+     * unfilled-then-flips flicker).
+     */
+    private fun currentMediaIdFlow(player: Player) = callbackFlow<String?> {
+        val listener = object : Player.Listener {
+            override fun onMediaItemTransition(item: MediaItem?, reason: Int) {
+                trySend(item?.mediaId)
+            }
+        }
+        player.addListener(listener)
+        awaitClose { player.removeListener(listener) }
+    }.onStart { emit(player.currentMediaItem?.mediaId) }
+
     override fun onGetSession(controllerInfo: MediaSession.ControllerInfo): MediaSession? =
         mediaSession
 
     override fun onTaskRemoved(rootIntent: Intent?) {
         val player = mediaSession?.player ?: return super.onTaskRemoved(rootIntent)
-        val activelyPlaying = player.playWhenReady && player.playbackState != Player.STATE_ENDED
+        // player.isPlaying is overridden on MinstrelForwardingPlayer to return
+        // remoteState.isPlaying while UPnP is active, so a swipe-away with
+        // Sonos playing keeps the service (and its UPnP poll loop) alive.
+        val activelyPlaying = player.isPlaying ||
+            (player.playWhenReady && player.playbackState != Player.STATE_ENDED)
         if (!activelyPlaying) {
             stopSelf()
         }
@@ -54,6 +189,7 @@ class MinstrelPlayerService : MediaSessionService() {
     }
 
     override fun onDestroy() {
+        serviceScope.cancel()
         mediaSession?.run {
             player.release()
             release()
@@ -61,4 +197,11 @@ class MinstrelPlayerService : MediaSessionService() {
         mediaSession = null
         super.onDestroy()
     }
+
+    private companion object {
+        // Stable request code for the session-activity PendingIntent.
+        // Arbitrary but distinct from any other PendingIntent we ever
+        // build against MainActivity.
+        const val REQUEST_OPEN_NOW_PLAYING = 0x100
+    }
 }

android/app/src/main/java/com/fabledsword/minstrel/player/OfflineGatedDataSource.kt

@@ -0,0 +1,78 @@
+package com.fabledsword.minstrel.player
+
+import androidx.media3.datasource.DataSource
+import androidx.media3.datasource.DataSpec
+import androidx.media3.datasource.TransferListener
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
+import com.fabledsword.minstrel.connectivity.ServerHealth
+import java.io.IOException
+import java.io.InterruptedIOException
+
+/**
+ * DataSource wrapper that fails the network read immediately when
+ * [NetworkStatusController] reports a gating state. CacheDataSource only
+ * calls this upstream factory on cache misses, so playback of cached audio is
+ * unaffected -- only "tap a non-cached track while offline" hits this branch
+ * and gets a fast, meaningful error instead of a multi-second network timeout
+ * (which then surfaced as a silent decode failure to the user).
+ *
+ * Wrapping rather than substituting the OkHttp data source lets the cache
+ * write path remain intact for when health returns and we DO want to fetch:
+ * we keep the same upstream all the time, just gate `open()`.
+ */
+class OfflineGatedDataSource(
+    private val delegate: DataSource,
+    private val health: NetworkStatusController,
+) : DataSource {
+
+    override fun open(dataSpec: DataSpec): Long {
+        gateOnHealth()
+        return try {
+            val opened = delegate.open(dataSpec)
+            health.reportSuccess() // bytes flowing from the server == reachable
+            opened
+        } catch (e: IOException) {
+            health.reportFailure() // real network read failed → arbitrate via /healthz
+            throw e
+        }
+    }
+
+    /** Fast-fail before touching the network when the server can't be reached. */
+    private fun gateOnHealth() {
+        when (health.state.value) {
+            ServerHealth.Offline -> throw OfflineException(
+                "Track not in the on-device cache and the device is offline.",
+            )
+            ServerHealth.ServerDown -> throw OfflineException(
+                "Track not in the on-device cache and the Minstrel server is unreachable.",
+            )
+            // Unstable is non-gating: still try the network. Healthy too.
+            ServerHealth.Unstable, ServerHealth.Healthy -> Unit
+        }
+    }
+
+    override fun close() = delegate.close()
+    override fun getUri() = delegate.uri
+    override fun read(buffer: ByteArray, offset: Int, length: Int): Int =
+        delegate.read(buffer, offset, length)
+    override fun addTransferListener(transferListener: TransferListener) =
+        delegate.addTransferListener(transferListener)
+    override fun getResponseHeaders() = delegate.responseHeaders
+}
+
+class OfflineGatedDataSourceFactory(
+    private val upstream: DataSource.Factory,
+    private val health: NetworkStatusController,
+) : DataSource.Factory {
+    override fun createDataSource(): DataSource =
+        OfflineGatedDataSource(upstream.createDataSource(), health)
+}
+
+/**
+ * Signals the audio-source error path that the request was denied because the
+ * device is offline / the server is unreachable. ExoPlayer's [androidx.media3
+ * .common.PlaybackException] catches it via [InterruptedIOException]'s
+ * `IOException` ancestor and surfaces it as a SOURCE error, which then flows
+ * through the existing [PlaybackErrorReporter] -> snackbar path.
+ */
+class OfflineException(message: String) : IOException(message)

android/app/src/main/java/com/fabledsword/minstrel/player/PlayEventsReporter.kt

@@ -6,6 +6,7 @@ import androidx.lifecycle.ProcessLifecycleOwner
 import com.fabledsword.minstrel.api.endpoints.EventsApi
 import com.fabledsword.minstrel.auth.AuthStore
 import com.fabledsword.minstrel.cache.mutations.MutationQueue
+import com.fabledsword.minstrel.cache.mutations.PlayEndedPayload
 import com.fabledsword.minstrel.cache.mutations.PlayOfflinePayload
 import com.fabledsword.minstrel.di.ApplicationScope
 import com.fabledsword.minstrel.models.wire.PlayEndedRequest
@@ -64,11 +65,24 @@ class PlayEventsReporter @Inject constructor(
     private var curLastPositionMs: Long = 0
     private var curDurationMs: Long = 0
 
+    // Whether the currently-tracked play is actively playing (vs paused).
+    // onStop reads this: a backgrounded play that's still playing is left
+    // to the live path (the foreground service keeps us alive), while a
+    // paused one is durably closed so a kill can't orphan its open row.
+    private var curPlaying: Boolean = false
+
     // Server play_event_id when the live play_started succeeded;
     // null if start failed/offline — then the close is captured into
     // the offline mutation queue instead of a live ended/skipped.
     private var openPlayEventId: String? = null
 
+    // True from beginTrack until startLive's play_started resolves. When a
+    // close races an in-flight start (id still null), the server row is
+    // being created but we've lost its id — we must NOT also enqueue an
+    // offline play (that would duplicate); the server auto-closes the
+    // orphan on the next play_started instead.
+    private var startInFlight: Boolean = false
+
     private var prevTrackId: String? = null
 
     init {
@@ -95,7 +109,7 @@ class PlayEventsReporter @Inject constructor(
     ) {
         // Track-change → close the prior tracked play.
         if (trackId != prevTrackId && curTrackId != null) {
-            closeCurrent(viaOffline = false)
+            closeCurrent()
         }
 
         // Entered playing for a new track → begin tracking it.
@@ -110,6 +124,7 @@ class PlayEventsReporter @Inject constructor(
         if (curTrackId != null && trackId == curTrackId) {
             curLastPositionMs = positionMs
             if (durationMs > 0) curDurationMs = durationMs
+            curPlaying = playing
         }
 
         prevTrackId = trackId
@@ -121,12 +136,18 @@ class PlayEventsReporter @Inject constructor(
         curSource = source
         curLastPositionMs = 0
         curDurationMs = durationMs
+        curPlaying = true
         openPlayEventId = null
+        startInFlight = true
         startLive(trackId = trackId, source = source)
     }
 
     private fun startLive(trackId: String, source: String?) {
-        val cid = resolveClientId() ?: return
+        val cid = resolveClientId()
+        if (cid == null) {
+            startInFlight = false
+            return
+        }
         scope.launch {
             try {
                 val response = api.playStarted(
@@ -144,56 +165,72 @@ class PlayEventsReporter @Inject constructor(
             ) {
                 // Offline / flaky — openPlayEventId stays null; close
                 // path will enqueue the completed play for replay.
+            } finally {
+                startInFlight = false
             }
         }
     }
 
-    private fun closeCurrent(viaOffline: Boolean) {
+    /**
+     * Closes the tracked play. Routes by whether the server already has an
+     * open row, NOT by caller context — this is what keeps background /
+     * track-change / failure paths from each minting a second row:
+     *  - open server row (id) → close it by id; on failure enqueue a durable
+     *    close-by-id (never an offline play).
+     *  - start in flight (no id yet) → leave it; the server auto-closes the
+     *    orphan on the next play_started. Enqueuing offline here would
+     *    duplicate the in-flight row.
+     *  - no server row at all → record the whole play offline.
+     *
+     * Always uses the actual position played; the server's skip rule
+     * (50%/30s defaults) classifies was_skipped from it.
+     */
+    private fun closeCurrent() {
         val trackId = curTrackId
         val startedAt = curStartedAt
         if (trackId == null || startedAt == null) {
             resetCurrent()
             return
         }
-        // Always send the actual position played to; the server's
-        // skip rule (50%/30s defaults, configurable) classifies
-        // was_skipped from this. If the track ran to completion the
-        // last observed position is ~= duration, which gives ratio ~1
-        // and the server records a non-skip. The COMPLETION_TOLERANCE
-        // rounding the prior shape did is no longer needed — the
-        // server's threshold is the source of truth.
         val durationMs = curLastPositionMs
         val source = curSource
         val id = openPlayEventId
-
-        if (!viaOffline && id != null) {
-            scope.launch {
-                try {
-                    api.playEnded(
-                        PlayEndedRequest(
-                            playEventId = id,
-                            durationPlayedMs = durationMs,
-                        ),
-                    )
-                } catch (
-                    @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
-                ) {
-                    enqueueOffline(trackId, startedAt, source, durationMs)
-                }
-            }
-        } else {
-            enqueueOffline(trackId, startedAt, source, durationMs)
+        val inFlight = startInFlight
+        when {
+            id != null -> closeById(id, durationMs)
+            inFlight -> Unit
+            else -> enqueueOffline(trackId, startedAt, source, durationMs)
         }
         resetCurrent()
     }
 
+    private fun closeById(id: String, durationMs: Long) {
+        scope.launch {
+            try {
+                api.playEnded(
+                    PlayEndedRequest(playEventId = id, durationPlayedMs = durationMs),
+                )
+            } catch (
+                @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
+            ) {
+                // Durable close-by-id (idempotent server-side) — survives a
+                // process kill without orphaning the open row or duplicating.
+                mutationQueue.enqueuePlayEnded(
+                    PlayEndedPayload(playEventId = id, durationPlayedMs = durationMs),
+                )
+            }
+        }
+    }
+
     private fun resetCurrent() {
         curTrackId = null
         curStartedAt = null
         curSource = null
         curLastPositionMs = 0
         curDurationMs = 0
+        curPlaying = false
         openPlayEventId = null
+        startInFlight = false
     }
 
     private fun enqueueOffline(
@@ -232,8 +269,17 @@ class PlayEventsReporter @Inject constructor(
     // ── Lifecycle: durable-close on app background / detach ────────
 
     override fun onStop(owner: LifecycleOwner) {
-        if (curTrackId != null) {
-            closeCurrent(viaOffline = true)
+        // App backgrounded. If the tracked play is still PLAYING, leave it
+        // alone: the foreground media service keeps the process — and this
+        // app-scope uiState collector — alive, so the live state machine
+        // closes the play accurately on the next real track change. Closing
+        // here (the old always-offline behavior) raced the collector's
+        // re-begin and minted a duplicate, skip-misclassified row on every
+        // screen-lock. Only durably close a PAUSED play, where no further
+        // progress will happen and a process kill would otherwise orphan the
+        // open server row. See docs/superpowers/2026-06-11 contract audit.
+        if (curTrackId != null && !curPlaying) {
+            closeCurrent()
         }
     }
 }

android/app/src/main/java/com/fabledsword/minstrel/player/PlaybackErrorReporter.kt

@@ -1,5 +1,6 @@
 package com.fabledsword.minstrel.player
 
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
 import com.fabledsword.minstrel.di.ApplicationScope
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.channels.Channel
@@ -13,19 +14,23 @@ import javax.inject.Singleton
 private const val DEBOUNCE_MS = 2_000L
 
 /**
- * Surfaces ExoPlayer track-load failures (404 / decoder failure /
- * premature EOS / network drop) as user-visible snackbar messages.
+ * Surfaces playback failures (load errors + zero-duration tracks) as
+ * user-visible snackbar messages AND admin-inbox reports.
  *
- * Without this the player just silently skips the dead track — the
- * worst kind of bug, because the user can't tell "this file is
- * broken" from "the app is flaky".
+ * Without the snackbar the player just silently skips the dead track —
+ * the worst kind of bug, because the user can't tell "this file is
+ * broken" from "the app is flaky". Without the admin report the
+ * operator never finds out the track is bad and the next user hits
+ * the same wall.
  *
- * Pattern mirrors Flutter's `playback_error_reporter.dart`: collect
- * per-error events from [PlayerController.playbackErrorEvents],
- * debounce in a 2s window, and emit "Couldn't play 'X' — skipping"
- * for a single error or "Skipped N unplayable tracks" when a burst
- * lands inside the window. Stops the user from seeing a stack of N
- * toasts on a network blip that fails N tracks in a row.
+ * The snackbar text mirrors Flutter's `playback_error_reporter.dart`:
+ * collect [PlayerController.playbackErrorEvents], debounce in a 2s
+ * window, emit "Couldn't play 'X' — skipping" for a single error or
+ * "Skipped N unplayable tracks" when a burst lands inside the window.
+ *
+ * The server report fires per event (no debounce) via
+ * [PlaybackErrorRepository], which handles the offline-first
+ * MutationQueue fallback per the standing rule for server writes.
  *
  * ShellScaffold collects [messages] into its existing snackbar host
  * so the reporter doesn't need its own UI surface. Constructed at
@@ -35,6 +40,8 @@ private const val DEBOUNCE_MS = 2_000L
 @Singleton
 class PlaybackErrorReporter @Inject constructor(
     private val playerController: PlayerController,
+    private val repository: PlaybackErrorRepository,
+    private val networkStatus: NetworkStatusController,
     @ApplicationScope private val scope: CoroutineScope,
 ) {
     private val outChannel = Channel<String>(Channel.BUFFERED)
@@ -46,8 +53,15 @@ class PlaybackErrorReporter @Inject constructor(
         scope.launch {
             val buffer = mutableListOf<String>()
             var debounceJob: kotlinx.coroutines.Job? = null
-            playerController.playbackErrorEvents.collect { title ->
-                buffer.add(title)
+            playerController.playbackErrorEvents.collect { event ->
+                // A track failing to play is ambiguous (dead server vs. one bad
+                // file) — let the controller arbitrate via /healthz. No-op when
+                // already Offline; cheap otherwise.
+                networkStatus.reportFailure()
+                // Fire-and-forget the server report — repository handles
+                // success/queue branching so callers don't see throws.
+                scope.launch { repository.report(event) }
+                buffer.add(event.title)
                 debounceJob?.cancel()
                 debounceJob = scope.launch {
                     delay(DEBOUNCE_MS)

android/app/src/main/java/com/fabledsword/minstrel/player/PlaybackErrorRepository.kt

@@ -0,0 +1,78 @@
+package com.fabledsword.minstrel.player
+
+import com.fabledsword.minstrel.api.endpoints.PlaybackErrorReportRequest
+import com.fabledsword.minstrel.api.endpoints.PlaybackErrorsApi
+import com.fabledsword.minstrel.auth.AuthStore
+import com.fabledsword.minstrel.cache.mutations.MutationQueue
+import com.fabledsword.minstrel.cache.mutations.PlaybackErrorReportPayload
+import retrofit2.Retrofit
+import retrofit2.create
+import java.util.UUID
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Writes a [PlaybackErrorEvent] to the server. Follows the standing
+ * offline-first rule for server writes: try the POST first, fall back
+ * to the MutationQueue on transport failure so a tracked report is
+ * never lost.
+ *
+ * Reused client_id comes from [AuthStore.clientId] — the same UUID-
+ * per-install identifier the play-events reporter already sends, so
+ * support can correlate playback errors with the surrounding plays.
+ */
+@Singleton
+class PlaybackErrorRepository @Inject constructor(
+    private val authStore: AuthStore,
+    private val mutationQueue: MutationQueue,
+    retrofit: Retrofit,
+) {
+    private val api: PlaybackErrorsApi = retrofit.create()
+
+    /**
+     * Reports a playback failure. Returns [Outcome.ACCEPTED] on a 2xx,
+     * [Outcome.QUEUED] when the call was buffered to the MutationQueue
+     * for later replay. Never throws — callers don't need a try block.
+     */
+    suspend fun report(event: PlaybackErrorEvent): Outcome {
+        val clientId = resolveClientId()
+        val payload = PlaybackErrorReportPayload(
+            trackId = event.trackId,
+            kind = event.kind,
+            detail = event.detail,
+            clientId = clientId,
+        )
+        return try {
+            api.report(
+                PlaybackErrorReportRequest(
+                    trackId = payload.trackId,
+                    kind = payload.kind,
+                    detail = payload.detail,
+                    clientId = payload.clientId,
+                ),
+            )
+            Outcome.ACCEPTED
+        } catch (
+            @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
+        ) {
+            // Intentional swallow — see LikesRepository.toggleLike for
+            // the same offline-first rationale.
+            mutationQueue.enqueuePlaybackErrorReport(payload)
+            Outcome.QUEUED
+        }
+    }
+
+    /**
+     * Returns the persisted client id, generating + persisting one on
+     * first read. Mirrors [PlayEventsReporter.resolveClientId] — the
+     * value is shared across all client-id-carrying surfaces.
+     */
+    private fun resolveClientId(): String {
+        authStore.clientId.value?.let { return it }
+        val fresh = UUID.randomUUID().toString()
+        authStore.setClientId(fresh)
+        return fresh
+    }
+
+    enum class Outcome { ACCEPTED, QUEUED }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/PlayerController.kt

@@ -3,6 +3,10 @@ package com.fabledsword.minstrel.player
 import android.content.ComponentName
 import android.content.Context
 import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
+import android.os.SystemClock
+import androidx.core.net.toUri
 import androidx.media3.common.MediaItem
 import androidx.media3.common.MediaMetadata
 import androidx.media3.common.Player
@@ -18,8 +22,10 @@ import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharedFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
@@ -57,7 +63,17 @@ class PlayerController @Inject constructor(
     @ApplicationContext private val context: Context,
     @ApplicationScope private val scope: CoroutineScope,
     private val radio: RadioController,
+    private val playerFactory: PlayerFactory,
+    private val activeUpnpHolder: com.fabledsword.minstrel.player.output.ActiveUpnpHolder,
+    private val remoteState: RemotePlayerState,
 ) {
+
+    /**
+     * UPnP drop events surfaced from [PlayerFactory.dropEvents]. NowPlaying
+     * collects this into its snackbar host so a transport / poll failure
+     * during UPnP playback shows "Disconnected from <name>" to the user.
+     */
+    val dropEvents: SharedFlow<String> = playerFactory.dropEvents
     private val sessionToken =
         SessionToken(context, ComponentName(context, MinstrelPlayerService::class.java))
 
@@ -68,13 +84,32 @@ class PlayerController @Inject constructor(
 
     /**
      * Per-error events for [com.fabledsword.minstrel.player.PlaybackErrorReporter].
-     * Emits the failing track's title (or `"Track"` when unknown) each
-     * time Media3's `onPlayerError` fires — not bound to the lifetime of
-     * any UI subscriber so a torn-down screen doesn't drop events.
-     * Conflated channel so backpressure can't stall the player loop.
+     * Fires twice: once when Media3's `onPlayerError` surfaces a load
+     * failure (decoder, transport, EOS), and once when the player
+     * reaches STATE_READY with a duration of zero / TIME_UNSET — the
+     * "track loaded but has no audio" case the user sees as the
+     * player sitting frozen on a track.
+     *
+     * Drift #561: this was originally Channel.CONFLATED, which silently
+     * dropped every emission except the latest each time the reporter
+     * loop wasn't actively reading. A network blip that failed 5
+     * tracks back-to-back would surface only the last failure to the
+     * snackbar (the "Skipped 5 unplayable tracks" coalescing path was
+     * dead code) AND only POST one playback_errors row to the admin
+     * inbox instead of 5. Buffered so every burst event reaches the
+     * reporter; default capacity is 64 which is well above any real
+     * burst rate.
      */
-    private val playbackErrorEventsChannel = Channel<String>(Channel.CONFLATED)
-    val playbackErrorEvents: Flow<String> = playbackErrorEventsChannel.receiveAsFlow()
+    private val playbackErrorEventsChannel = Channel<PlaybackErrorEvent>(Channel.BUFFERED)
+    val playbackErrorEvents: Flow<PlaybackErrorEvent> = playbackErrorEventsChannel.receiveAsFlow()
+
+    /**
+     * Tracks which queue index has already been evaluated for the
+     * zero-duration / load-failed checks so STATE_READY firing
+     * repeatedly (after every seek, pause/resume) doesn't re-emit
+     * the same error event. Reset on each onMediaItemTransition.
+     */
+    private var lastEvaluatedItemIndex: Int = -1
 
     /**
      * Stable queue snapshot kept in sync with the player's MediaItems —
@@ -83,17 +118,50 @@ class PlayerController @Inject constructor(
      */
     private var queueRefs: List<TrackRef> = emptyList()
 
+    /**
+     * Completes when [mediaController] is non-null and the listener has
+     * been attached. Used by [awaitReady] so cold-boot callers like
+     * [ResumeController] can wait for the IPC bind before calling
+     * transport methods that would otherwise no-op silently. Drift
+     * #562 caught the race where a fast restore() landed before the
+     * MediaSessionService connection was up, silently dropping the
+     * restored queue.
+     */
+    private val readyDeferred = kotlinx.coroutines.CompletableDeferred<Unit>()
+
     init {
         scope.launch { connectAndObserve() }
     }
 
+    /**
+     * Suspends until the MediaController binding to
+     * [MinstrelPlayerService] is up and a Player.Listener is attached,
+     * so a subsequent transport call (setQueue, startRadio, playNext,
+     * …) will actually reach the player rather than being silently
+     * swallowed by the `mediaController ?: return` guards.
+     */
+    suspend fun awaitReady(): Unit = readyDeferred.await()
+
     // ── Transport (no-op until the controller is connected) ──────────────
 
-    fun play() { mediaController?.play() }
-    fun pause() { mediaController?.pause() }
-    fun seekTo(positionMs: Long) { mediaController?.seekTo(positionMs) }
-    fun skipToNext() { mediaController?.seekToNextMediaItem() }
-    fun skipToPrevious() { mediaController?.seekToPreviousMediaItem() }
+    // Each transport call must run on the MediaController's
+    // applicationLooper; calling from a background coroutine throws
+    // IllegalStateException (see PlayerController.setQueue's note).
+    // UI tap handlers are already on Main so the in-place branch hits;
+    // the background path only fires for cross-thread callers like
+    // OutputPickerController.selectUpnp (which calls pause() after
+    // handing playback off to a UPnP renderer).
+    fun play() { mediaController?.let { runOnControllerThread(it) { it.play() } } }
+    fun pause() { mediaController?.let { runOnControllerThread(it) { it.pause() } } }
+    fun seekTo(positionMs: Long) {
+        mediaController?.let { runOnControllerThread(it) { it.seekTo(positionMs) } }
+    }
+    fun skipToNext() {
+        mediaController?.let { runOnControllerThread(it) { it.seekToNextMediaItem() } }
+    }
+    fun skipToPrevious() {
+        mediaController?.let { runOnControllerThread(it) { it.seekToPreviousMediaItem() } }
+    }
 
     /** Flip shuffle on/off. Media3 emits onEvents → uiState reflects. */
     fun toggleShuffle() {
@@ -125,18 +193,49 @@ class PlayerController @Inject constructor(
     }
 
     /**
-     * Replace the queue with [tracks] and start playing from [initialIndex].
+     * Replace the queue with [tracks] starting at [initialIndex].
      * [source] tags the queue with its origin (e.g. "for_you") so the
      * server-side rotation reporter can advance it; carried in
      * MediaItem extras.
+     *
+     * [autoplay] controls whether playback starts immediately. The
+     * default is true to preserve the "user pressed play on a tile"
+     * UX every existing caller relies on. Drift #560: cold-boot
+     * resume passes autoplay = false so the persisted queue is
+     * restored without auto-starting playback after the user has
+     * been away from the app — starting audio on cold launch was
+     * surprising for users who had paused mid-track before
+     * backgrounding.
      */
-    fun setQueue(tracks: List<TrackRef>, initialIndex: Int = 0, source: String? = null) {
+    fun setQueue(
+        tracks: List<TrackRef>,
+        initialIndex: Int = 0,
+        source: String? = null,
+        autoplay: Boolean = true,
+    ) {
         val controller = mediaController ?: return
         queueRefs = tracks
         val items = tracks.map { it.toMediaItem(source) }
-        controller.setMediaItems(items, initialIndex, /* startPositionMs = */ 0L)
-        controller.prepare()
-        controller.play()
+        // Drift #562 cold-boot resume calls this from a non-Main suspend
+        // context after awaitReady() unblocks (ResumeController launches
+        // on Dispatchers.Default by the time it reaches us). MediaController
+        // enforces application-thread access and throws
+        // IllegalStateException otherwise — post to its applicationLooper
+        // if we're already there, run directly to avoid the re-dispatch
+        // latency UI callers depend on.
+        runOnControllerThread(controller) {
+            controller.setMediaItems(items, initialIndex, /* startPositionMs = */ 0L)
+            controller.prepare()
+            if (autoplay) controller.play()
+        }
+    }
+
+    private fun runOnControllerThread(controller: MediaController, block: () -> Unit) {
+        if (Looper.myLooper() == controller.applicationLooper) {
+            block()
+        } else {
+            Handler(controller.applicationLooper).post(block)
+        }
     }
 
     /**
@@ -166,17 +265,92 @@ class PlayerController @Inject constructor(
     }
 
     /**
-     * Seed a fresh radio queue from [trackId] and start playback.
-     * Replaces the existing queue. The `source` tag is "radio:<id>"
-     * so the server-side rotation reporter can distinguish radio
-     * plays from album / playlist plays. No-op on an empty server
-     * response; throws on transport / non-2xx for the caller to
-     * surface in a snackbar.
+     * Seed a fresh radio queue from [trackId]. The `source` tag is
+     * "radio:<id>" so the server-side rotation reporter can
+     * distinguish radio plays from album / playlist plays.
+     *
+     * Two modes:
+     *  - Nothing in the queue: start the radio cold from track 0
+     *    (the seed plays first, recommendations follow).
+     *  - Queue already populated: do NOT interrupt — keep the current
+     *    track playing as-is, trim every upcoming track, and append
+     *    the radio results after the current item. If the seed is the
+     *    currently playing track (the common "tap Start Radio on the
+     *    song I'm listening to" case), drop it from the appended list
+     *    so it doesn't immediately repeat. This is an intentional
+     *    divergence from Flutter's `playerActions.startRadio`, which
+     *    always calls `playTracks` and restarts playback from 0.
+     *
+     * No-op on an empty server response; throws on transport / non-2xx
+     * for the caller to surface in a snackbar.
      */
     suspend fun startRadio(trackId: String) {
+        val controller = mediaController ?: return
         val tracks = radio.seed(trackId)
         if (tracks.isEmpty()) return
-        setQueue(tracks, initialIndex = 0, source = "radio:$trackId")
+        val source = "radio:$trackId"
+        if (controller.mediaItemCount == 0) {
+            setQueue(tracks, initialIndex = 0, source = source)
+        } else {
+            appendRadioToQueue(controller, tracks, trackId, source)
+        }
+    }
+
+    /**
+     * Mid-queue radio insert. The current track keeps playing; every
+     * upcoming item is removed; the radio results are appended after.
+     * Drops the seed from the appended list when it matches the
+     * currently-playing track so it doesn't immediately repeat.
+     */
+    private fun appendRadioToQueue(
+        controller: MediaController,
+        tracks: List<TrackRef>,
+        seedTrackId: String,
+        source: String,
+    ) {
+        val currentIdx = controller.currentMediaItemIndex
+        val currentTrack = queueRefs.getOrNull(currentIdx)
+        val toAppend = if (currentTrack?.id == seedTrackId) tracks.drop(1) else tracks
+        if (toAppend.isEmpty()) return
+        val nextIdx = currentIdx + 1
+        if (nextIdx < controller.mediaItemCount) {
+            controller.removeMediaItems(nextIdx, controller.mediaItemCount)
+        }
+        queueRefs = queueRefs.take(nextIdx) + toAppend
+        controller.addMediaItems(toAppend.map { it.toMediaItem(source) })
+    }
+
+    /**
+     * When a STATE_READY transition for a freshly-loaded item reports
+     * a zero / TIME_UNSET duration, fire a `zero_duration` error event
+     * and advance past the dead track. Otherwise no-op.
+     */
+    private fun handleZeroDurationIfNeeded(controller: MediaController, idx: Int) {
+        // Skip during UPnP playback (active) AND during the activation load
+        // window (target set, active not yet wired). ExoPlayer is intentionally
+        // paused throughout both windows so its STATE_READY duration is always
+        // 0 / TIME_UNSET -- without this guard we rapid-advance through the
+        // entire local queue (and spam /api/playback-errors).
+        val current = queueRefs.getOrNull(idx)
+        val upnpEngaged = activeUpnpHolder.active.value != null ||
+            activeUpnpHolder.target.value != null
+        if (current == null || upnpEngaged) return
+        val duration = controller.duration
+        val isZeroDuration = duration <= 0L || duration == androidx.media3.common.C.TIME_UNSET
+        if (!isZeroDuration) return
+        playbackErrorEventsChannel.trySend(
+            PlaybackErrorEvent(
+                trackId = current.id,
+                kind = "zero_duration",
+                title = current.title.ifEmpty { "Track" },
+                detail = "duration=$duration",
+            ),
+        )
+        if (controller.hasNextMediaItem()) {
+            controller.seekToNextMediaItem()
+        } else {
+            controller.stop()
+        }
     }
 
     // ── Internal: async connect + Listener-driven UI state sync ──────────
@@ -196,16 +370,61 @@ class PlayerController @Inject constructor(
                 return
             }
         mediaController = controller
+        // Drift #562: signal awaitReady() callers (ResumeController et al.)
+        // that the controller is bound. Listener is attached below in
+        // the same coroutine so by the time downstream code runs after
+        // awaitReady, the Player.Listener is wired too.
+        if (!readyDeferred.isCompleted) readyDeferred.complete(Unit)
         startPositionPolling(controller)
+        // Keep isUpnpLoading current between player-event fires: holder state
+        // changes (setTarget / set(active)) are independent of Media3 events, so
+        // onEvents alone would lag behind by up to one event cycle. This collector
+        // runs for the process lifetime alongside the position poller.
+        scope.launch {
+            combine(
+                activeUpnpHolder.target,
+                activeUpnpHolder.active,
+            ) { target, active -> target != null && active == null }
+                .collect { isLoading ->
+                    uiStateInternal.value = uiStateInternal.value.copy(isUpnpLoading = isLoading)
+                }
+        }
         controller.addListener(
             object : Player.Listener {
                 override fun onPlayerError(error: androidx.media3.common.PlaybackException) {
-                    val title = queueRefs
-                        .getOrNull(controller.currentMediaItemIndex)
-                        ?.title
-                        ?.takeIf { it.isNotEmpty() }
-                        ?: "Track"
-                    playbackErrorEventsChannel.trySend(title)
+                    val current = queueRefs.getOrNull(controller.currentMediaItemIndex)
+                    val title = current?.title?.takeIf { it.isNotEmpty() } ?: "Track"
+                    val trackId = current?.id ?: return
+                    playbackErrorEventsChannel.trySend(
+                        PlaybackErrorEvent(
+                            trackId = trackId,
+                            kind = "load_failed",
+                            title = title,
+                            detail = error.message,
+                        ),
+                    )
+                }
+
+                override fun onMediaItemTransition(
+                    mediaItem: androidx.media3.common.MediaItem?,
+                    reason: Int,
+                ) {
+                    // Reset the per-item evaluation guard so the new
+                    // item's STATE_READY transition gets a fresh check.
+                    lastEvaluatedItemIndex = -1
+                    // The track flipped -- re-anchor the position interpolator
+                    // so the next polling tick treats the new track's
+                    // remoteState.positionMs as fresh rather than carrying the
+                    // old anchor + elapsed forward.
+                    lastSeenRemotePositionMs = -1L
+                }
+
+                override fun onPlaybackStateChanged(playbackState: Int) {
+                    if (playbackState != Player.STATE_READY) return
+                    val idx = controller.currentMediaItemIndex
+                    if (idx == lastEvaluatedItemIndex) return
+                    lastEvaluatedItemIndex = idx
+                    handleZeroDurationIfNeeded(controller, idx)
                 }
 
                 override fun onEvents(player: Player, events: Player.Events) {
@@ -215,15 +434,38 @@ class PlayerController @Inject constructor(
                         ?.mediaMetadata
                         ?.extras
                         ?.getString(MINSTREL_SOURCE_KEY)
+                    val isUpnpLoading = activeUpnpHolder.target.value != null &&
+                        activeUpnpHolder.active.value == null
+                    // When UPnP is active, the wrapped ExoPlayer is paused with
+                    // no real audio loaded -- player.duration / isPlaying /
+                    // currentPosition all reflect that. Read from remoteState
+                    // instead so an onEvents fire (e.g. activity resume) doesn't
+                    // clobber the UI with zeros. Duration falls back to the
+                    // wrapped player's value when Sonos hasn't reported one yet
+                    // (pre-first-poll window, or Sonos still buffering) -- the
+                    // wrapped ExoPlayer was prepared with the same MediaItem so
+                    // it knows the real duration before any SOAP poll lands.
+                    val upnpActive = activeUpnpHolder.active.value != null
                     uiStateInternal.value =
                         PlayerUiState(
                             currentTrack = current,
                             queue = queueRefs,
                             queueIndex = idx,
-                            isPlaying = player.isPlaying,
-                            isBuffering = player.playbackState == Player.STATE_BUFFERING,
-                            positionMs = player.currentPosition.coerceAtLeast(0),
-                            durationMs = player.duration.coerceAtLeast(0),
+                            isPlaying = if (upnpActive) remoteState.isPlaying else player.isPlaying,
+                            isBuffering = !upnpActive &&
+                                player.playbackState == Player.STATE_BUFFERING,
+                            positionMs = if (upnpActive) {
+                                remoteState.positionMs
+                            } else {
+                                player.currentPosition
+                            }.coerceAtLeast(0),
+                            durationMs = effectiveDuration(
+                                upnpActive,
+                                remoteState.durationMs,
+                                player.duration,
+                                desiredIdx = idx,
+                                controllerIdx = idx,
+                            ),
                             bufferedPositionMs = player.bufferedPosition.coerceAtLeast(0),
                             playbackError = player.playerError?.message,
                             currentSource = source,
@@ -233,6 +475,7 @@ class PlayerController @Inject constructor(
                                 Player.REPEAT_MODE_ONE -> RepeatMode.ONE
                                 else -> RepeatMode.OFF
                             },
+                            isUpnpLoading = isUpnpLoading,
                         )
                 }
             },
@@ -257,15 +500,138 @@ class PlayerController @Inject constructor(
         scope.launch(Dispatchers.Main.immediate) {
             while (isActive) {
                 delay(POSITION_POLL_INTERVAL_MS)
-                if (!controller.isPlaying) continue
-                uiStateInternal.value = uiStateInternal.value.copy(
-                    positionMs = controller.currentPosition.coerceAtLeast(0),
-                    bufferedPositionMs = controller.bufferedPosition.coerceAtLeast(0),
-                )
+                tickPositionPoll(controller)
             }
         }
     }
 
+    /**
+     * One position-polling tick. Owns track-change detection too: when UPnP
+     * is active and the wrapped ExoPlayer is paused, `delegate.seekTo` from
+     * `maybeSyncLocalCursor` may not fire `onMediaItemTransition`, leaving
+     * uiState.queueIndex stuck on the old track even after Sonos has
+     * advanced. So the tick reads Sonos's reported Track as the source of
+     * truth, rebuilds the index/title fields itself, and force-syncs the
+     * wrapped player as defense in depth.
+     */
+    private fun tickPositionPoll(controller: MediaController) {
+        val upnpActive = activeUpnpHolder.active.value != null
+        resolvePendingTransport(controller, upnpActive)
+        val pendingTransport = upnpActive && remoteState.pendingTransportDeadlineMs > 0L
+        val effectiveIsPlaying =
+            if (upnpActive) remoteState.isPlaying else controller.isPlaying
+        val effectivePosition = if (upnpActive) {
+            interpolatedRemotePosition(effectiveIsPlaying)
+        } else {
+            controller.currentPosition
+        }
+        val desiredIdx = desiredQueueIndex(controller, upnpActive)
+        val current = uiStateInternal.value
+        val newPos = effectivePosition.coerceAtLeast(0)
+        val newDur = effectiveDuration(
+            upnpActive,
+            remoteState.durationMs,
+            controller.duration,
+            desiredIdx = desiredIdx,
+            controllerIdx = controller.currentMediaItemIndex,
+        )
+        val newBuf = controller.bufferedPosition.coerceAtLeast(0)
+        // Track adjustments are forward-only AND suppressed while a user
+        // transport press is pending Sonos confirmation. Together those keep
+        // either direction of user input from being undone by a stale poll.
+        val trackChanged = !pendingTransport &&
+            desiredIdx > current.queueIndex &&
+            desiredIdx in queueRefs.indices
+        publishTickIfChanged(
+            current, trackChanged, desiredIdx,
+            effectiveIsPlaying, newPos, newDur, newBuf,
+        )
+    }
+
+    /**
+     * Event-driven primary path: clear pending the moment Sonos's reported
+     * Track matches the wrapped player's index. Safety fallback: clear on
+     * deadline so we don't ignore Sonos's actual state forever if SOAP fails.
+     */
+    private fun resolvePendingTransport(controller: MediaController, upnpActive: Boolean) {
+        if (!upnpActive || remoteState.pendingTransportDeadlineMs <= 0L) return
+        val sonosIdx = (remoteState.trackNumber - 1).coerceAtLeast(0)
+        val timedOut = SystemClock.elapsedRealtime() > remoteState.pendingTransportDeadlineMs
+        if (sonosIdx == controller.currentMediaItemIndex || timedOut) {
+            remoteState.clearPendingTransport()
+        }
+    }
+
+    @Suppress("LongParameterList") // assembled at one tick call site; refactor would cost clarity
+    private fun publishTickIfChanged(
+        current: PlayerUiState,
+        trackChanged: Boolean,
+        desiredIdx: Int,
+        effectiveIsPlaying: Boolean,
+        newPos: Long,
+        newDur: Long,
+        newBuf: Long,
+    ) {
+        val somethingChanged = trackChanged ||
+            current.isPlaying != effectiveIsPlaying ||
+            current.positionMs != newPos ||
+            current.durationMs != newDur
+        if (!somethingChanged) return
+        val newTrack = if (trackChanged) queueRefs[desiredIdx] else current.currentTrack
+        val newIdx = if (trackChanged) desiredIdx else current.queueIndex
+        uiStateInternal.value = current.copy(
+            currentTrack = newTrack,
+            queueIndex = newIdx,
+            isPlaying = effectiveIsPlaying,
+            positionMs = newPos,
+            durationMs = newDur,
+            bufferedPositionMs = newBuf,
+        )
+        // Intentionally do NOT call controller.seekTo here. That would route
+        // through MinstrelForwardingPlayer's seekTo override and re-issue
+        // AVTransport.SeekToTrack to Sonos -- which seeks Sonos back to the
+        // start of the same track it's already playing, restarting the song.
+        // The wrapped player's index is kept in sync by maybeSyncLocalCursor's
+        // delegate.seekTo (which bypasses the override). If it lags briefly,
+        // the next pollOnce catches up; the uiState above already reflects
+        // Sonos's truth for the user.
+    }
+
+    private fun desiredQueueIndex(controller: MediaController, upnpActive: Boolean): Int =
+        if (upnpActive) {
+            (remoteState.trackNumber - 1).coerceAtLeast(0)
+        } else {
+            controller.currentMediaItemIndex
+        }
+
+    // ── Remote position interpolation state ──────────────────────────────
+    // remoteState.positionMs is only refreshed by ForwardingPlayer's 1Hz
+    // SOAP poll (and only when the round-trip completes -- screen-off WiFi
+    // sleep can stall it for many seconds). To keep the scrubber moving
+    // smoothly we anchor each fresh reading + an elapsed-realtime stamp;
+    // between updates we display anchor + elapsed when Sonos is playing.
+    // A real correction lands as soon as the next poll arrives.
+    @Volatile private var lastSeenRemotePositionMs: Long = -1L
+    @Volatile private var positionAnchorMs: Long = 0L
+    @Volatile private var positionAnchorAtRealtimeMs: Long = 0L
+
+    private fun interpolatedRemotePosition(isPlaying: Boolean): Long {
+        val raw = remoteState.positionMs
+        val now = SystemClock.elapsedRealtime()
+        if (raw != lastSeenRemotePositionMs) {
+            lastSeenRemotePositionMs = raw
+            positionAnchorMs = raw
+            positionAnchorAtRealtimeMs = now
+        }
+        if (!isPlaying) return positionAnchorMs
+        // Cap how far past the last anchor we extrapolate. After
+        // MAX_INTERPOLATION_DRIFT_MS without a poll update, freeze the
+        // displayed position at anchor + cap rather than projecting wildly.
+        // The next successful poll re-anchors and motion resumes.
+        val delta = (now - positionAnchorAtRealtimeMs).coerceAtMost(MAX_INTERPOLATION_DRIFT_MS)
+        return positionAnchorMs + delta
+    }
+
     /**
      * Bridges Media3's `ListenableFuture<MediaController>.buildAsync()`
      * to a suspend function without pulling in `kotlinx-coroutines-guava`
@@ -301,7 +667,23 @@ class PlayerController @Inject constructor(
             .setArtist(artistName)
             .setAlbumTitle(albumTitle)
             .apply {
+                // Server-known duration -- gives the lock-screen / notification
+                // scrubber a real total even when the wrapped ExoPlayer is
+                // paused under UPnP (it never probes a duration in that state).
+                if (durationSec > 0) setDurationMs(durationSec.toLong() * MS_PER_SECOND)
                 if (source != null) setExtras(sourceExtras(source))
+                // Point the notification / lock-screen art at the SAME album
+                // cover the in-app surfaces use (TrackRef.coverUrl ->
+                // /api/albums/{id}/cover). Without this, Media3 falls back to
+                // whatever art is embedded in the stream's tags, which can be a
+                // different image than the server's album cover. Setting
+                // artworkUri here is load-bearing: MediaMetadata.populate()
+                // overwrites artworkUri + artworkData as a pair, so the
+                // MediaItem's URI clears any embedded artworkData ExoPlayer
+                // extracts from the stream -- the cover endpoint wins on both
+                // surfaces. The session's OkHttp-backed BitmapLoader (see
+                // PlayerFactory) is what makes this authed placeholder URL load.
+                if (coverUrl.isNotEmpty()) setArtworkUri(coverUrl.toUri())
             }
             .build()
         // Server's stream_url is a relative path (/api/tracks/{id}/stream);
@@ -323,8 +705,40 @@ class PlayerController @Inject constructor(
     private fun sourceExtras(source: String): Bundle =
         Bundle().apply { putString(MINSTREL_SOURCE_KEY, source) }
 
+    /**
+     * Duration to surface to the UI. Priority: Sonos's reported duration
+     * (only when UPnP active and non-zero) -> wrapped ExoPlayer's value
+     * (only valid once it's probed the stream) -> TrackRef.durationSec
+     * (always known from the server response). The third tier is what
+     * keeps the scrubber populated when the user taps Sonos before the
+     * wrapped player has had time to probe its own duration -- without
+     * it, both top tiers report 0/TIME_UNSET and the field reads empty
+     * until the first SOAP poll lands.
+     */
+    @Suppress("ReturnCount") // 3-tier fallback reads cleanest as a ladder of early returns
+    private fun effectiveDuration(
+        upnpActive: Boolean,
+        remoteMs: Long,
+        localMs: Long,
+        desiredIdx: Int,
+        controllerIdx: Int,
+    ): Long {
+        if (upnpActive && remoteMs > 0) return remoteMs
+        // Tier 2 (wrapped player's probed duration) only valid when the
+        // wrapped player is on the same track we're trying to show. After a
+        // Sonos natural advance the polling tick updates desiredIdx from
+        // Sonos's truth while controllerIdx is briefly stale -- using the
+        // wrapped player's duration here would surface the old track's
+        // length under the new track's title.
+        if (localMs > 0 && controllerIdx == desiredIdx) return localMs
+        val ref = queueRefs.getOrNull(desiredIdx) ?: return 0
+        return ref.durationSec.toLong() * MS_PER_SECOND
+    }
+
     companion object {
         const val MINSTREL_SOURCE_KEY: String = "minstrel_source"
+        private const val MS_PER_SECOND = 1_000L
+        private const val MAX_INTERPOLATION_DRIFT_MS = 5_000L
     }
 }
 
@@ -334,3 +748,19 @@ class PlayerController @Inject constructor(
 // surfaces are driven by Media3's MediaSession callbacks separately;
 // they don't need this poll.
 private const val POSITION_POLL_INTERVAL_MS = 500L
+
+/**
+ * Structured playback failure event for [PlaybackErrorReporter]. Drives
+ * both the user-facing snackbar ("Couldn't play X — skipping") and the
+ * /api/playback-errors admin inbox.
+ *
+ * `kind` is one of "zero_duration" / "load_failed" / "stalled" matching
+ * the server's CHECK constraint. `detail` is free-text (the Media3
+ * error message, the observed duration value, etc.).
+ */
+data class PlaybackErrorEvent(
+    val trackId: String,
+    val kind: String,
+    val title: String,
+    val detail: String? = null,
+)

android/app/src/main/java/com/fabledsword/minstrel/player/PlayerFactory.kt

@@ -3,7 +3,10 @@ package com.fabledsword.minstrel.player
 import android.content.Context
 import androidx.media3.common.AudioAttributes
 import androidx.media3.common.C
+import androidx.media3.common.Player
+import androidx.media3.common.util.BitmapLoader
 import androidx.media3.database.StandaloneDatabaseProvider
+import androidx.media3.datasource.DataSourceBitmapLoader
 import androidx.media3.datasource.cache.CacheDataSink
 import androidx.media3.datasource.cache.CacheDataSource
 import androidx.media3.datasource.cache.LeastRecentlyUsedCacheEvictor
@@ -11,15 +14,21 @@ import androidx.media3.datasource.cache.SimpleCache
 import androidx.media3.datasource.okhttp.OkHttpDataSource
 import androidx.media3.exoplayer.ExoPlayer
 import androidx.media3.exoplayer.source.DefaultMediaSourceFactory
+import androidx.media3.session.CacheBitmapLoader
 import com.fabledsword.minstrel.cache.audiocache.CacheConfig
+import com.fabledsword.minstrel.player.output.ActiveUpnpHolder
 import dagger.hilt.android.qualifiers.ApplicationContext
+import kotlinx.coroutines.channels.BufferOverflow
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.SharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
 import okhttp3.OkHttpClient
 import java.io.File
 import javax.inject.Inject
 import javax.inject.Singleton
 
 /**
- * Builds the process-singleton ExoPlayer with our shared OkHttp +
+ * Builds the process-singleton player with our shared OkHttp +
  * SimpleCache chain. The MinstrelPlayerService (Phase 6.2) calls
  * `build()` once during onCreate.
  *
@@ -31,12 +40,22 @@ import javax.inject.Singleton
  * (sizeBytes cap = rollingCap); our policy layer in the worker layers
  * the 2-bucket protection on top by feeding `removeSpan` only for
  * unprotected tracks.
+ *
+ * `build()` returns a [MinstrelForwardingPlayer] wrapping the internal
+ * ExoPlayer. When the UPnP route drops (3 consecutive poll failures or
+ * a SOAP failure), [dropEvents] emits the route name so the NowPlaying
+ * surface can show a snackbar. The MutableSharedFlow uses DROP_OLDEST
+ * with capacity=1 so a burst of failures during a single tear-down
+ * surfaces as one event rather than queueing N.
  */
 @Singleton
 class PlayerFactory @Inject constructor(
     @ApplicationContext private val context: Context,
     private val okHttpClient: OkHttpClient,
     private val cacheConfig: CacheConfig,
+    private val activeUpnpHolder: ActiveUpnpHolder,
+    private val remoteState: RemotePlayerState,
+    private val serverHealth: com.fabledsword.minstrel.connectivity.NetworkStatusController,
 ) {
     private val cacheDir: File = File(context.cacheDir, "audio_cache").apply { mkdirs() }
 
@@ -46,11 +65,36 @@ class PlayerFactory @Inject constructor(
         StandaloneDatabaseProvider(context),
     )
 
-    fun build(): ExoPlayer {
+    // MutableSharedFlow with extraBufferCapacity=1 + DROP_OLDEST so a burst
+    // of drop events (rapid SOAP failures during a single tear-down) surfaces
+    // as one snackbar rather than queueing N.
+    private val dropEventsInternal = MutableSharedFlow<String>(
+        replay = 0,
+        extraBufferCapacity = 1,
+        onBufferOverflow = BufferOverflow.DROP_OLDEST,
+    )
+    val dropEvents: SharedFlow<String> = dropEventsInternal.asSharedFlow()
+
+    fun build(): Player {
+        val exo = buildExoPlayer()
+        return MinstrelForwardingPlayer(
+            delegate = exo,
+            holder = activeUpnpHolder,
+            remoteState = remoteState,
+            onDrop = { name -> emitDrop(name) },
+        )
+    }
+
+    private fun buildExoPlayer(): ExoPlayer {
         val httpDataSource = OkHttpDataSource.Factory(okHttpClient)
+        // Gate network reads on ServerHealth so a cache miss while offline
+        // fails fast with an OfflineException instead of hitting an OkHttp
+        // timeout. CacheDataSource only consults the upstream factory on a
+        // cache miss, so playback of cached audio is unaffected.
+        val gatedUpstream = OfflineGatedDataSourceFactory(httpDataSource, serverHealth)
         val cacheDataSource = CacheDataSource.Factory()
             .setCache(simpleCache)
-            .setUpstreamDataSourceFactory(httpDataSource)
+            .setUpstreamDataSourceFactory(gatedUpstream)
             .setCacheWriteDataSinkFactory(
                 CacheDataSink.Factory()
                     .setCache(simpleCache)
@@ -71,4 +115,26 @@ class PlayerFactory @Inject constructor(
             .setHandleAudioBecomingNoisy(true)
             .build()
     }
+
+    /**
+     * BitmapLoader for the MediaSession's notification / lock-screen art.
+     * Backed by the shared [okHttpClient] so it inherits the same
+     * BaseUrlInterceptor placeholder rewrite + auth cookie that Coil uses
+     * for in-app covers — without it the default DefaultHttpDataSource
+     * loader can't resolve `http://placeholder.invalid/...` and would 401
+     * on the cover endpoint. Wrapped in CacheBitmapLoader so a cover the
+     * notification already fetched isn't re-loaded on every metadata
+     * refresh. Lets the album-cover artworkUri set in
+     * [PlayerController.toMediaItem] actually render on the media card.
+     */
+    fun buildBitmapLoader(): BitmapLoader =
+        CacheBitmapLoader(
+            DataSourceBitmapLoader.Builder(context)
+                .setDataSourceFactory(OkHttpDataSource.Factory(okHttpClient))
+                .build(),
+        )
+
+    private fun emitDrop(routeName: String) {
+        dropEventsInternal.tryEmit(routeName)
+    }
 }

android/app/src/main/java/com/fabledsword/minstrel/player/PlayerUiState.kt

@@ -28,4 +28,6 @@ data class PlayerUiState(
     val currentSource: String? = null,
     val shuffleEnabled: Boolean = false,
     val repeatMode: RepeatMode = RepeatMode.OFF,
+    /** True while the UPnP initial-batch load is in progress (target set, active not yet wired). */
+    val isUpnpLoading: Boolean = false,
 )

android/app/src/main/java/com/fabledsword/minstrel/player/RemotePlayerState.kt

@@ -0,0 +1,110 @@
+package com.fabledsword.minstrel.player
+
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Synthesized state for the UPnP route -- what the ForwardingPlayer
+ * exposes via Player.getCurrentPosition / isPlaying / etc. when the
+ * remote leg is active. Not a Player; a container.
+ *
+ * Updates flow in from:
+ *  - 1Hz GetPositionInfo poll -> applyPositionInfo()
+ *  - Transport SOAP calls landing 200 OK -> applyTransport{Playing,Paused,Stopped}()
+ *  - Poll failures -> recordPollFailure()
+ *
+ * The poll-failure counter is the sole drop arbiter: [DROP_THRESHOLD]
+ * consecutive poll failures = remote considered dropped (returns true
+ * from recordPollFailure for the caller to surface). Any success resets it.
+ * Failed transport commands no longer drop the route -- they retry and
+ * otherwise defer to this counter (see MinstrelForwardingPlayer).
+ */
+@Singleton
+class RemotePlayerState @Inject constructor() {
+
+    @Volatile var positionMs: Long = 0L; private set
+    @Volatile var durationMs: Long = 0L; private set
+    @Volatile var isPlaying: Boolean = false; private set
+    @Volatile var currentTrackUri: String = ""; private set
+    @Volatile var lastError: Throwable? = null; private set
+    @Volatile var trackNumber: Int = 0; private set
+
+    // The operator's last explicit transport intent (play=true, pause=false),
+    // distinct from the observed remote isPlaying. handleRemoteDrop resumes
+    // local playback based on THIS, not isPlaying -- so a play() that fails
+    // its SOAP (stale/dead renderer) still resumes on the phone instead of
+    // swallowing the tap. Deliberately NOT cleared by applyError.
+    @Volatile var lastPlayIntent: Boolean = false; private set
+
+    // Pending-transport deadline (SystemClock.elapsedRealtime() at which we
+    // give up waiting). When > 0, a user transport action (next/prev/seekTo
+    // idx) is in flight: ForwardingPlayer has already moved the wrapped
+    // player's index, but Sonos's reported Track hasn't refreshed via a
+    // SOAP poll yet. PlayerController.tickPositionPoll skips track
+    // adjustments while pending is non-zero. Pending clears when:
+    //   (a) [event-driven, primary] a poll lands and Sonos's reported Track
+    //       matches the wrapped player's currentMediaItemIndex; or
+    //   (b) [safety fallback] the deadline expires (covers SOAP-fail cases
+    //       where Sonos never acks).
+    @Volatile var pendingTransportDeadlineMs: Long = 0L; private set
+
+    fun beginPendingTransport(deadlineMs: Long) {
+        pendingTransportDeadlineMs = deadlineMs
+    }
+
+    fun clearPendingTransport() {
+        pendingTransportDeadlineMs = 0L
+    }
+
+    @Volatile private var consecutivePollFailures: Int = 0
+
+    fun applyPositionInfo(positionMs: Long, durationMs: Long, trackUri: String, trackNumber: Int) {
+        this.positionMs = positionMs
+        this.durationMs = durationMs
+        this.currentTrackUri = trackUri
+        this.trackNumber = trackNumber
+    }
+
+    fun applyTransportPlaying() { isPlaying = true }
+    fun applyTransportPaused() { isPlaying = false }
+    fun applyTransportStopped() {
+        isPlaying = false
+        positionMs = 0L
+    }
+
+    fun setPlayIntent(intended: Boolean) { lastPlayIntent = intended }
+
+    fun applyError(t: Throwable) {
+        isPlaying = false
+        lastError = t
+    }
+
+    /** Returns true when the rolling threshold trips this call. */
+    fun recordPollFailure(): Boolean {
+        consecutivePollFailures += 1
+        return consecutivePollFailures >= DROP_THRESHOLD
+    }
+
+    fun recordPollSuccess() { consecutivePollFailures = 0 }
+
+    fun reset() {
+        positionMs = 0L
+        durationMs = 0L
+        isPlaying = false
+        lastPlayIntent = false
+        currentTrackUri = ""
+        lastError = null
+        consecutivePollFailures = 0
+        trackNumber = 0
+        pendingTransportDeadlineMs = 0L
+    }
+
+    private companion object {
+        // ~30 seconds of consecutive poll failures before declaring the route
+        // dropped. Bumped from 3 because screen-off WiFi sleep / brief Doze
+        // can stall socket I/O for several seconds without the renderer
+        // actually being unreachable -- a 3-failure drop kicked us back to
+        // local audio every time the phone went into a pocket.
+        const val DROP_THRESHOLD = 30
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/ResumeController.kt

@@ -54,12 +54,22 @@ class ResumeController @Inject constructor(
                 .getOrNull()
                 ?.takeIf { it.tracks.isNotEmpty() }
                 ?: return
+        // Drift #562: wait for the MediaController binding before
+        // calling setQueue, otherwise restore() racing the IPC
+        // handshake silently drops the persisted queue (PlayerController
+        // setQueue early-returns when mediaController is null).
+        playerController.awaitReady()
         playerController.setQueue(
             tracks = payload.tracks,
             initialIndex = payload.queueIndex
                 .coerceAtLeast(0)
                 .coerceAtMost(payload.tracks.lastIndex),
             source = payload.source,
+            // Drift #560: cold-boot resume must NOT auto-start
+            // playback. The user has been away from the app; starting
+            // audio on cold launch is surprising. They tap play to
+            // resume. Queue + position are restored; transport is idle.
+            autoplay = false,
         )
         // PositionMs not seeked yet — Player connection may still be
         // establishing; the seek call would no-op. Acceptable to start

android/app/src/main/java/com/fabledsword/minstrel/player/StreamTokenProvider.kt

@@ -0,0 +1,24 @@
+package com.fabledsword.minstrel.player
+
+import com.fabledsword.minstrel.api.endpoints.CastApi
+import com.fabledsword.minstrel.api.endpoints.StreamTokenRequest
+import com.fabledsword.minstrel.api.endpoints.StreamTokenResponse
+import retrofit2.Retrofit
+import retrofit2.create
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Mints stream tokens for a given track id. Pulled into its own Hilt
+ * singleton so [MinstrelForwardingPlayer] (service-side) and
+ * [com.fabledsword.minstrel.player.output.OutputPickerController]
+ * (controller-side) don't each construct their own [CastApi] from
+ * Retrofit. The shared Retrofit instance is unchanged.
+ */
+@Singleton
+class StreamTokenProvider @Inject constructor(retrofit: Retrofit) {
+    private val api: CastApi = retrofit.create()
+
+    suspend fun mint(trackId: String): StreamTokenResponse =
+        api.streamToken(StreamTokenRequest(trackId = trackId))
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/ActiveUpnpHolder.kt

@@ -0,0 +1,43 @@
+package com.fabledsword.minstrel.player.output
+
+import com.fabledsword.minstrel.player.output.upnp.AVTransportClient
+import com.fabledsword.minstrel.player.output.upnp.RenderingControlClient
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Shared singleton handle to the currently-active UPnP route's transport
+ * + rendering clients. Decouples [com.fabledsword.minstrel.player.MinstrelForwardingPlayer]
+ * from [OutputPickerController] -- the picker writes; the forwarding
+ * player reads. Null = no UPnP active (local ExoPlayer path).
+ */
+data class ActiveUpnp(
+    val routeId: String,
+    val routeName: String,
+    val avTransport: AVTransportClient,
+    val rendering: RenderingControlClient?,
+)
+
+@Singleton
+class ActiveUpnpHolder @Inject constructor() {
+
+    private val internal = MutableStateFlow<ActiveUpnp?>(null)
+    val active: StateFlow<ActiveUpnp?> = internal.asStateFlow()
+
+    /**
+     * Pending route id during selectUpnp's queue-load window. Set when
+     * loadQueueOnSonos starts; cleared on completion (success or failure).
+     * ForwardingPlayer overrides treat (target != null && active == null)
+     * as "UPnP intended but SOAP not yet wired" -- drop transport commands
+     * silently rather than send them to a half-loaded queue.
+     */
+    private val targetInternal = MutableStateFlow<String?>(null)
+    val target: StateFlow<String?> = targetInternal.asStateFlow()
+
+    fun set(active: ActiveUpnp?) { internal.value = active }
+
+    fun setTarget(routeId: String?) { targetInternal.value = routeId }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/DeviceChip.kt

@@ -0,0 +1,84 @@
+package com.fabledsword.minstrel.player.output
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import com.composables.icons.lucide.Bluetooth
+import com.composables.icons.lucide.Cast
+import com.composables.icons.lucide.ChevronDown
+import com.composables.icons.lucide.Headphones
+import com.composables.icons.lucide.Lucide
+import com.composables.icons.lucide.Smartphone
+import com.composables.icons.lucide.Speaker
+
+/**
+ * Spotify-style chip showing the current output route. Sits between
+ * BottomActionsRow and ScrubberRow in NowPlayingScreen. Tap to open
+ * the picker sheet.
+ *
+ * Visibility rule per the spec: hidden when the route list has
+ * exactly one entry AND that entry is BuiltIn — no reason to surface
+ * a picker for "the only thing available." Visibility logic owned
+ * by the caller (NowPlayingScreen).
+ */
+@Composable
+fun DeviceChip(
+    route: OutputRoute,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    Surface(
+        modifier = modifier,
+        onClick = onClick,
+        shape = MaterialTheme.shapes.medium,
+        color = MaterialTheme.colorScheme.surfaceVariant,
+    ) {
+        Row(
+            modifier = Modifier.padding(horizontal = 12.dp, vertical = 8.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(8.dp),
+        ) {
+            Icon(
+                imageVector = iconFor(route.kind),
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.size(CHIP_ICON_DP.dp),
+            )
+            Text(
+                text = route.name,
+                style = MaterialTheme.typography.labelLarge,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+            )
+            Icon(
+                imageVector = Lucide.ChevronDown,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.size(CHIP_CHEVRON_DP.dp),
+            )
+        }
+    }
+}
+
+internal fun iconFor(kind: OutputRoute.Kind): ImageVector = when (kind) {
+    OutputRoute.Kind.BuiltIn -> Lucide.Smartphone
+    OutputRoute.Kind.Wired -> Lucide.Headphones
+    OutputRoute.Kind.Bluetooth -> Lucide.Bluetooth
+    OutputRoute.Kind.Cast -> Lucide.Cast
+    OutputRoute.Kind.Other -> Lucide.Speaker
+}
+
+private const val CHIP_ICON_DP = 16
+private const val CHIP_CHEVRON_DP = 14

android/app/src/main/java/com/fabledsword/minstrel/player/output/IdleRevertAction.kt

@@ -0,0 +1,21 @@
+package com.fabledsword.minstrel.player.output
+
+/** Action the idle-revert collector should take on a player-state change. */
+internal enum class IdleRevertAction { ARM, CANCEL, IGNORE }
+
+/**
+ * Pure decision for the UPnP idle-revert timer. [armed] is whether the
+ * idle timer Job is currently running. We ARM only on the transition INTO
+ * "engaged + not playing" (so repeated paused emissions don't reset the
+ * countdown), CANCEL whenever playback resumes or UPnP disengages, and
+ * otherwise IGNORE.
+ */
+internal fun idleRevertAction(
+    upnpEngaged: Boolean,
+    isPlaying: Boolean,
+    armed: Boolean,
+): IdleRevertAction = when {
+    upnpEngaged && !isPlaying -> if (armed) IdleRevertAction.IGNORE else IdleRevertAction.ARM
+    armed -> IdleRevertAction.CANCEL
+    else -> IdleRevertAction.IGNORE
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/OutputPickerController.kt

@@ -0,0 +1,711 @@
+@file:Suppress("TooManyFunctions") // 5 MediaRouter.Callback overrides inflate the count
+package com.fabledsword.minstrel.player.output
+
+import android.content.Context
+import androidx.mediarouter.media.MediaControlIntent
+import androidx.mediarouter.media.MediaRouteSelector
+import androidx.mediarouter.media.MediaRouter
+import com.fabledsword.minstrel.di.ApplicationScope
+import com.fabledsword.minstrel.models.TrackRef
+import com.fabledsword.minstrel.player.PlayerController
+import com.fabledsword.minstrel.player.PlayerFactory
+import com.fabledsword.minstrel.player.RemotePlayerState
+import com.fabledsword.minstrel.player.StreamTokenProvider
+import com.fabledsword.minstrel.player.output.upnp.AVTransportClient
+import com.fabledsword.minstrel.player.output.upnp.RenderingControlClient
+import com.fabledsword.minstrel.player.output.upnp.SoapClient
+import com.fabledsword.minstrel.player.output.upnp.SoapFaultException
+import com.fabledsword.minstrel.player.output.upnp.UpnpDiscoveryController
+import com.fabledsword.minstrel.player.output.upnp.bareUdn
+import dagger.hilt.android.qualifiers.ApplicationContext
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import okhttp3.OkHttpClient
+import timber.log.Timber
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Snapshot of the audio output route state. [current] is the live
+ * route audio is being delivered to. [available] is every route the
+ * picker knows about -- MediaRouter system routes merged with
+ * UPnP/DLNA renderers discovered on the LAN -- with the BuiltIn
+ * "Phone speaker" pinned first, everything else alphabetical.
+ */
+data class RouteSnapshot(
+    val current: OutputRoute,
+    val available: List<OutputRoute>,
+)
+
+/**
+ * Hilt-singleton facade over [MediaRouter] + [UpnpDiscoveryController].
+ * Owns the callback lifecycle — default passive behavior at process
+ * start (route list updates without forcing Bluetooth scans), upgrades
+ * to active discovery while the picker sheet is open so newly-paired
+ * devices appear promptly. The [routesState] StateFlow projects the
+ * current route + sorted available list as a [RouteSnapshot]; the
+ * picker ViewModel collects it.
+ *
+ * Selection branches on [OutputRoute.Protocol]:
+ *  - [OutputRoute.Protocol.SYSTEM] — MediaRouter.selectRoute (built-in,
+ *    wired, Bluetooth)
+ *  - [OutputRoute.Protocol.UPNP] — mint a signed stream token via
+ *    [StreamTokenProvider.mint], drive the discovered renderer with
+ *    AVTransport.SetAVTransportURI + Play, pause local playback so
+ *    audio yields to the network speaker
+ *  - [OutputRoute.Protocol.CAST] / [OutputRoute.Protocol.SONOS] —
+ *    reserved for follow-up slices; ignored for now.
+ *
+ * Mirrors the OutputPickerController role described in
+ * docs/superpowers/specs/2026-06-03-android-output-picker-bluetooth-design.md
+ * and the UPnP extensions in
+ * docs/superpowers/specs/2026-06-03-android-output-picker-upnp-design.md.
+ */
+@Singleton
+class OutputPickerController @Inject constructor(
+    @ApplicationContext private val context: Context,
+    @ApplicationScope private val scope: CoroutineScope,
+    private val upnpDiscovery: UpnpDiscoveryController,
+    private val playerController: PlayerController,
+    private val playerFactory: PlayerFactory,
+    private val streamTokens: StreamTokenProvider,
+    private val activeUpnpHolder: ActiveUpnpHolder,
+    private val remoteState: RemotePlayerState,
+    private val okHttp: OkHttpClient,
+) {
+    private val mediaRouter = MediaRouter.getInstance(context)
+
+    private val selector = MediaRouteSelector.Builder()
+        .addControlCategory(MediaControlIntent.CATEGORY_LIVE_AUDIO)
+        .build()
+
+    /**
+     * Internal projection of the live MediaRouter snapshot. Refreshed
+     * on every Callback event; combined downstream with UPnP routes
+     * into the public [routesState].
+     */
+    private val systemRoutesInternal = MutableStateFlow(snapshotFromRouter())
+
+    private val selectedUpnpRouteIdInternal = MutableStateFlow<String?>(null)
+    private val selectUpnpMutex = Mutex()
+
+    val routesState: StateFlow<RouteSnapshot> = combine(
+        systemRoutesInternal,
+        upnpDiscovery.routes,
+        upnpDiscovery.sonosTopology,
+        selectedUpnpRouteIdInternal,
+    ) { sys, upnp, _, upnpSelected ->
+        val suppressed = upnpDiscovery.nonCoordinatorMemberUdns()
+        val visibleUpnp = upnp
+            .filter { it.id.bareUdn() !in suppressed } // suppressed set is bare UDNs
+            .map { OutputRoute.fromUpnpRoute(it) }
+        val merged = sys.available + visibleUpnp
+        val current = if (upnpSelected != null) {
+            merged.firstOrNull { it.id == upnpSelected } ?: sys.current
+        } else {
+            sys.current
+        }
+        RouteSnapshot(current = current, available = sortRoutes(merged))
+    }.stateIn(scope, SharingStarted.Eagerly, systemRoutesInternal.value)
+
+    private val callback = object : MediaRouter.Callback() {
+        override fun onRouteAdded(router: MediaRouter, route: MediaRouter.RouteInfo) =
+            refresh()
+
+        override fun onRouteChanged(router: MediaRouter, route: MediaRouter.RouteInfo) =
+            refresh()
+
+        override fun onRouteRemoved(router: MediaRouter, route: MediaRouter.RouteInfo) =
+            refresh()
+
+        override fun onRouteSelected(
+            router: MediaRouter,
+            route: MediaRouter.RouteInfo,
+            reason: Int,
+        ) = refresh()
+
+        override fun onRouteUnselected(
+            router: MediaRouter,
+            route: MediaRouter.RouteInfo,
+            reason: Int,
+        ) = refresh()
+    }
+
+    // Last-synced queue identity. Used by observeQueueChangesForSonosResync
+    // to detect when the user has mutated the queue (full replacement,
+    // playNext insert, or radio-append) while UPnP is active and apply the
+    // minimum-incremental set of Sonos SOAP operations to bring its native
+    // queue back in sync. Stored as the full id list (not a join-key) so we
+    // can run the longest-common-prefix / common-suffix diff.
+    private var lastSyncedQueueIds: List<String>? = null
+
+    // Idle-revert timer. Armed when playback is paused/stopped on a UPnP
+    // route; fires revertToPhoneOnIdle after IDLE_REVERT_MS of continuous
+    // non-playing. Cancelled on resume, route change, or explicit disconnect.
+    // See idleRevertAction for the arm/cancel decision.
+    private var idleRevertJob: Job? = null
+
+    init {
+        // Two-arg addCallback registers with no discovery flag —
+        // androidx.mediarouter 1.7.0's default passive behavior:
+        // route-list updates flow through onRouteAdded/Removed/Changed
+        // without forcing Bluetooth scans. (There is no
+        // CALLBACK_FLAG_PASSIVE_DISCOVERY constant; absent flag = passive.)
+        mediaRouter.addCallback(selector, callback)
+        // When MinstrelForwardingPlayer reports the active UPnP route has
+        // dropped (the poll loop's consecutive-failure threshold tripping --
+        // the sole drop arbiter; a failed transport command no longer drops),
+        // clear the UPnP selection state and fall back to local ExoPlayer at
+        // the last-known remote position. This mirrors selectSystem's disconnect
+        // path but skips the Stop SOAP since the device is already unreachable.
+        scope.launch {
+            playerFactory.dropEvents.collect { handleRemoteDrop() }
+        }
+        scope.launch { observeQueueChangesForSonosResync() }
+        scope.launch { observeIdleRevertWhileUpnp() }
+    }
+
+    /**
+     * Arm/cancel the idle-revert timer as playback state changes while a
+     * UPnP route is engaged. "Engaged" = active OR target set, so the brief
+     * selectUpnp/resync window (active momentarily null, target set) doesn't
+     * spuriously fire. The arm/cancel choice is the pure idleRevertAction.
+     */
+    private suspend fun observeIdleRevertWhileUpnp() {
+        playerController.uiState.collect { state ->
+            val engaged = activeUpnpHolder.active.value != null ||
+                activeUpnpHolder.target.value != null
+            val armed = idleRevertJob?.isActive == true
+            when (idleRevertAction(engaged, state.isPlaying, armed)) {
+                IdleRevertAction.ARM ->
+                    idleRevertJob = scope.launch {
+                        delay(IDLE_REVERT_MS)
+                        revertToPhoneOnIdle()
+                    }
+                IdleRevertAction.CANCEL -> {
+                    idleRevertJob?.cancel()
+                    idleRevertJob = null
+                }
+                IdleRevertAction.IGNORE -> Unit
+            }
+        }
+    }
+
+    /**
+     * Timer fired: the operator paused on a UPnP route and never resumed.
+     * Stop the renderer (best-effort -- it's reachable, unlike a drop),
+     * clear the UPnP overlay so routesState falls back to the phone, and
+     * seek local ExoPlayer to the last remote position. No play(): the
+     * operator was paused, so we revert routing silently. Guarded by the
+     * selectUpnpMutex so it can't race selectUpnp/resync.
+     */
+    private suspend fun revertToPhoneOnIdle() = selectUpnpMutex.withLock {
+        if (remoteState.isPlaying) return@withLock // resumed at the boundary
+        val active = activeUpnpHolder.active.value
+        val capturedPositionMs = remoteState.positionMs
+        runCatching { active?.avTransport?.stop() }
+            .onFailure { Timber.w(it, "UPnP Stop failed during idle revert") }
+        activeUpnpHolder.set(null)
+        activeUpnpHolder.setTarget(null)
+        selectedUpnpRouteIdInternal.value = null
+        idleRevertJob = null
+        playerController.seekTo(capturedPositionMs)
+    }
+
+    /**
+     * When the user plays a different playlist while Sonos is active,
+     * PlayerController.setQueue replaces the local queue but Sonos's
+     * native queue still holds the OLD tracks. MinstrelForwardingPlayer's
+     * setMediaItems override clears holder.active + sets target so the
+     * imminent play() call drops (drops via isLoadingUpnp() = true). Then
+     * this collector observes the uiState.queue change and re-runs
+     * loadQueueOnSonos to push the new tracks to Sonos.
+     *
+     * Discrimination: selectUpnp's initial-load path doesn't change
+     * uiState.queue (the queue was already populated before route
+     * selection), so this collector doesn't fire during that window. Only
+     * a fresh setQueue from PlayerController bumps the joined-ids key.
+     */
+    private suspend fun observeQueueChangesForSonosResync() {
+        playerController.uiState.collect { state ->
+            val newIds = state.queue.map { it.id }
+            val oldIds = lastSyncedQueueIds
+            if (newIds == oldIds) return@collect
+            lastSyncedQueueIds = newIds
+            // Route can be in target (setMediaItems-induced clearing already
+            // ran in ForwardingPlayer) OR in active (queue changed via
+            // addMediaItem / removeMediaItems etc. which don't hit the
+            // markPending hook).
+            val routeId = activeUpnpHolder.target.value
+                ?: activeUpnpHolder.active.value?.routeId
+                ?: return@collect
+            if (state.queue.isEmpty()) {
+                Timber.w("Sonos resync skipped: empty queue (clearing target)")
+                activeUpnpHolder.setTarget(null)
+                return@collect
+            }
+            scope.launch {
+                resyncSonosQueue(routeId, oldIds.orEmpty(), state.queue, state.queueIndex)
+            }
+        }
+    }
+
+    /**
+     * Bring Sonos's native queue back in sync with the local queue after a
+     * mutation. Tries an incremental SOAP diff first (RemoveTrackRangeFromQueue
+     * + AddURIToQueue at the insertion point) so playback continues without
+     * interruption -- that's what playNext / radio-append want. Falls back to
+     * the full removeAllTracks + reload path when the diff implies the current
+     * Sonos track was deleted (e.g. user switched playlists), which is what
+     * the user-reported "Sonos queue does not update" bug needed.
+     */
+    private suspend fun resyncSonosQueue(
+        routeId: String,
+        oldIds: List<String>,
+        newQueue: List<TrackRef>,
+        newCurrentIndex: Int,
+    ) = selectUpnpMutex.withLock {
+        val upnpRoute = upnpDiscovery.routes.value.firstOrNull { it.id == routeId }
+        val transport = upnpDiscovery.transportFor(routeId)
+        if (upnpRoute == null || transport == null) {
+            Timber.w(
+                "Sonos resync: route or transport gone for %s, dropping to local",
+                routeId,
+            )
+            activeUpnpHolder.setTarget(null)
+            selectedUpnpRouteIdInternal.value = null
+            return@withLock
+        }
+        val handledIncrementally = runCatching {
+            tryIncrementalResync(transport, oldIds, newQueue)
+        }.getOrElse { e ->
+            Timber.w(e, "Sonos incremental resync errored; falling back to full reload")
+            false
+        }
+        if (handledIncrementally) {
+            // Active was never cleared on the incremental path; clear any
+            // target that markPendingResyncIfRemote set (it didn't, for
+            // incremental cases that don't go through setMediaItems, but
+            // belt-and-suspenders).
+            activeUpnpHolder.setTarget(null)
+            return@withLock
+        }
+        // Full rebuild: ensure active is cleared so transport calls drop
+        // (markPendingResyncIfRemote may already have done this on the
+        // setMediaItems path).
+        if (activeUpnpHolder.active.value != null) {
+            activeUpnpHolder.set(null)
+            activeUpnpHolder.setTarget(routeId)
+        }
+        val outputRoute = OutputRoute.fromUpnpRoute(upnpRoute)
+        val rendering = renderingClientFor(routeId)
+        Timber.w("Sonos resync: full reload of %d tracks on %s", newQueue.size, outputRoute.name)
+        runCatching {
+            loadQueueOnSonos(transport, outputRoute, newQueue, newCurrentIndex)
+            activeUpnpHolder.set(
+                ActiveUpnp(
+                    routeId = routeId,
+                    routeName = outputRoute.name,
+                    avTransport = transport,
+                    rendering = rendering,
+                ),
+            )
+            activeUpnpHolder.setTarget(null)
+        }.onFailure { e ->
+            Timber.w(e, "Sonos resync (full) failed -- dropping to local")
+            activeUpnpHolder.setTarget(null)
+            selectedUpnpRouteIdInternal.value = null
+        }
+    }
+
+    /**
+     * Diff-based incremental Sonos queue sync. Returns true when the new
+     * queue can be produced from the old one with a remove-then-insert at
+     * the same middle slice -- the common-prefix and common-suffix portions
+     * stay untouched, and the current Sonos track must lie in the preserved
+     * prefix (otherwise the diff would orphan playback). Returns false to
+     * signal the caller to fall back to a full reload.
+     */
+    private suspend fun tryIncrementalResync(
+        transport: AVTransportClient,
+        oldIds: List<String>,
+        newQueue: List<TrackRef>,
+    ): Boolean {
+        val newIds = newQueue.map { it.id }
+        if (oldIds == newIds) return true
+        val prefixLen = commonPrefixLength(oldIds, newIds)
+        val suffixLen = commonSuffixLength(
+            oldIds.subList(prefixLen, oldIds.size),
+            newIds.subList(prefixLen, newIds.size),
+        )
+        val removedCount = oldIds.size - prefixLen - suffixLen
+        val addedCount = newIds.size - prefixLen - suffixLen
+        // Sonos's current track number is 1-based; compare against the
+        // preserved-prefix range as 0-based. If the current track is in
+        // the removed slice, incremental can't preserve playback -- caller
+        // falls back to full rebuild.
+        val currentSonosIdx0 = remoteState.trackNumber - 1
+        val canApply = currentSonosIdx0 in 0 until prefixLen
+        if (canApply) {
+            applyQueueDiff(transport, newQueue, prefixLen, removedCount, addedCount)
+        } else {
+            Timber.w(
+                "Sonos incremental: current track %d not in preserved prefix [0,%d); full rebuild",
+                currentSonosIdx0,
+                prefixLen,
+            )
+        }
+        return canApply
+    }
+
+    private suspend fun applyQueueDiff(
+        transport: AVTransportClient,
+        newQueue: List<TrackRef>,
+        prefixLen: Int,
+        removedCount: Int,
+        addedCount: Int,
+    ) {
+        if (removedCount > 0) {
+            Timber.w(
+                "Sonos incremental: RemoveTrackRangeFromQueue start=%d count=%d",
+                prefixLen + 1,
+                removedCount,
+            )
+            transport.removeTrackRangeFromQueue(
+                startingIndex = prefixLen + 1,
+                numberOfTracks = removedCount,
+            )
+        }
+        if (addedCount == 0) return
+        Timber.w(
+            "Sonos incremental: AddURIToQueue x%d starting at position %d",
+            addedCount,
+            prefixLen + 1,
+        )
+        for (i in 0 until addedCount) {
+            val ref = newQueue[prefixLen + i]
+            val token = streamTokens.mint(ref.id)
+            transport.addURIToQueue(
+                uri = token.url,
+                mime = token.mime,
+                title = token.title,
+                enqueuedURIPosition = prefixLen + i + 1,
+            )
+            if (i > 0) delay(EXTEND_THROTTLE_MS)
+        }
+    }
+
+    private fun commonPrefixLength(a: List<String>, b: List<String>): Int {
+        val limit = minOf(a.size, b.size)
+        for (i in 0 until limit) {
+            if (a[i] != b[i]) return i
+        }
+        return limit
+    }
+
+    private fun commonSuffixLength(a: List<String>, b: List<String>): Int {
+        val limit = minOf(a.size, b.size)
+        for (i in 0 until limit) {
+            if (a[a.size - 1 - i] != b[b.size - 1 - i]) return i
+        }
+        return limit
+    }
+
+    /**
+     * Called when the active UPnP route drops unexpectedly (the poll loop's
+     * consecutive-failure threshold tripping). Captures the last remote
+     * position + play state, clears UPnP selection, and resumes local ExoPlayer at
+     * the same point. Skips the Stop SOAP (device already unreachable).
+     * The snackbar is handled independently by the NowPlaying surface
+     * collecting the same [PlayerFactory.dropEvents] via PlayerController.
+     */
+    private fun handleRemoteDrop() {
+        val capturedPositionMs = remoteState.positionMs
+        // Resume on the operator's last play-intent, not the observed remote
+        // state: after a pause, isPlaying is false, but a failed play() that
+        // triggered this drop means the operator DID ask to play -- honor it.
+        val wasPlayingRemote = remoteState.lastPlayIntent
+        activeUpnpHolder.set(null)
+        activeUpnpHolder.setTarget(null)
+        selectedUpnpRouteIdInternal.value = null
+        playerController.seekTo(capturedPositionMs)
+        if (wasPlayingRemote) playerController.play()
+    }
+
+    /**
+     * Upgrade callback registration to active discovery — call when
+     * the picker sheet opens so newly-paired Bluetooth devices
+     * surface within a few seconds, and fire an SSDP M-SEARCH burst
+     * for UPnP renderers. Idempotent: re-registering with a
+     * new flag set replaces the prior registration in MediaRouter.
+     */
+    fun upgradeDiscovery() {
+        mediaRouter.addCallback(selector, callback, MediaRouter.CALLBACK_FLAG_REQUEST_DISCOVERY)
+        upnpDiscovery.upgradeDiscovery()
+    }
+
+    /**
+     * Downgrade callback registration back to default passive behavior
+     * — call when the picker sheet closes so we don't keep Bluetooth
+     * scanning on for battery cost. Two-arg overload = no flag =
+     * passive. Same idempotent re-registration semantics. The UPnP
+     * side has no symmetric downgrade (passive SSDP NOTIFY listen is
+     * always on); the call is preserved for API parity.
+     */
+    fun downgradeDiscovery() {
+        mediaRouter.addCallback(selector, callback)
+        upnpDiscovery.downgradeDiscovery()
+    }
+
+    /**
+     * Select [route]. SYSTEM routes hand off to [MediaRouter]; UPNP
+     * routes mint a signed stream token + drive AVTransport on the
+     * discovered renderer + pause local playback. Other protocols
+     * (CAST / SONOS) are reserved for follow-up slices and are
+     * silently ignored — the picker shouldn't show them yet.
+     */
+    fun select(route: OutputRoute) {
+        when (route.protocol) {
+            OutputRoute.Protocol.SYSTEM -> selectSystem(route)
+            OutputRoute.Protocol.UPNP -> scope.launch { selectUpnp(route) }
+            OutputRoute.Protocol.CAST, OutputRoute.Protocol.SONOS -> Unit
+        }
+    }
+
+    private fun selectSystem(route: OutputRoute) {
+        val wasUpnp = selectedUpnpRouteIdInternal.value
+        if (wasUpnp != null) {
+            val active = activeUpnpHolder.active.value
+            val capturedPositionMs = remoteState.positionMs
+            val wasPlayingRemote = remoteState.isPlaying
+            scope.launch {
+                runCatching { active?.avTransport?.stop() }
+                    .onFailure { Timber.w(it, "UPnP Stop failed during disconnect") }
+                activeUpnpHolder.set(null)
+                activeUpnpHolder.setTarget(null)
+                selectedUpnpRouteIdInternal.value = null
+                playerController.seekTo(capturedPositionMs)
+                if (wasPlayingRemote) playerController.play()
+            }
+        }
+        val target = mediaRouter.routes.firstOrNull { it.id == route.id } ?: return
+        mediaRouter.selectRoute(target)
+    }
+
+    /**
+     * Drive the UPnP renderer using Sonos native queue mode:
+     * clear the device's queue, load every track from our local queue
+     * via AddURIToQueue, point the transport at the queue URI, seek to
+     * the current index, and play. Wrapped in `runCatching` — SOAP
+     * failure abandons the selection cleanly.
+     *
+     * Order of operations is deliberate:
+     *  1. Pause local so the user doesn't keep hearing local audio.
+     *  2. Set target early so ForwardingPlayer drops transport taps
+     *     while the 17-second queue load is in progress.
+     *  3. Wire active LAST (after loadQueueOnSonos) so SOAP commands
+     *     are never routed to a half-loaded Sonos queue.
+     */
+    private suspend fun selectUpnp(route: OutputRoute) = selectUpnpMutex.withLock {
+        val uiState = playerController.uiState.value
+        val currentTrack = uiState.currentTrack
+        if (currentTrack == null) {
+            Timber.w("UPnP select skipped: no currentTrack (start playback first)")
+            return@withLock
+        }
+        // Honor Sonos topology: pick the coordinator's route when the user
+        // tapped a group row. Suppression in routesState already keeps the
+        // visible row at the coordinator's id, so this is identity in the
+        // common case -- defensive for follow-up flows.
+        val effectiveRoute = upnpDiscovery.coordinatorRouteFor(route.id)
+            ?.let { OutputRoute.fromUpnpRoute(it) } ?: route
+        val transport = upnpDiscovery.transportFor(effectiveRoute.id)
+        if (transport == null) {
+            Timber.w(
+                "UPnP select skipped: no transport for route id=${effectiveRoute.id} " +
+                    "(route disappeared or id mismatch with discovery list)",
+            )
+            return@withLock
+        }
+        val rendering = renderingClientFor(effectiveRoute.id)
+        // Pause local before flipping UI state -- user shouldn't keep hearing
+        // local audio while we queue up Sonos.
+        playerController.pause()
+        selectedUpnpRouteIdInternal.value = effectiveRoute.id
+        // Mark UPnP loading. ForwardingPlayer overrides drop transport commands
+        // silently while target is set but active is null -- the user's premature
+        // taps don't hit Sonos's stale state from a prior session.
+        activeUpnpHolder.setTarget(effectiveRoute.id)
+        runCatching {
+            loadQueueOnSonos(transport, effectiveRoute, uiState.queue, uiState.queueIndex)
+            // Wire active LAST -- SOAP path is now safe to use.
+            activeUpnpHolder.set(
+                ActiveUpnp(
+                    routeId = effectiveRoute.id,
+                    routeName = effectiveRoute.name,
+                    avTransport = transport,
+                    rendering = rendering,
+                ),
+            )
+            // Selecting a route loads the queue and Plays on the renderer, so
+            // the standing intent is "play" -- a later drop should resume local.
+            remoteState.setPlayIntent(true)
+        }.onFailure { e ->
+            Timber.w(e, "UPnP select failed for route ${effectiveRoute.id}")
+            activeUpnpHolder.set(null)
+            activeUpnpHolder.setTarget(null)
+            selectedUpnpRouteIdInternal.value = null
+        }
+    }
+
+    private suspend fun loadQueueOnSonos(
+        transport: AVTransportClient,
+        route: OutputRoute,
+        queue: List<TrackRef>,
+        currentIndex: Int,
+    ) {
+        Timber.w("UPnP select: clear queue on %s", route.name)
+        transport.removeAllTracksFromQueue()
+        val initialEnd = (currentIndex + 1).coerceAtMost(queue.size)
+        val initialBatch = queue.subList(0, initialEnd)
+        Timber.w(
+            "UPnP select: add %d initial tracks (currentIndex=%d, totalQueue=%d)",
+            initialBatch.size, currentIndex, queue.size,
+        )
+        initialBatch.forEachIndexed { idx, ref ->
+            val token = streamTokens.mint(ref.id)
+            transport.addURIToQueue(
+                uri = token.url,
+                mime = token.mime,
+                title = token.title,
+                enqueuedURIPosition = idx + 1,
+            )
+        }
+        val coordinatorUdn = route.id.bareUdn()
+        val queueUri = "x-rincon-queue:$coordinatorUdn#0"
+        Timber.w("UPnP select: SetAVTransportURI %s", queueUri)
+        transport.setAVTransportURI(queueUri, "")
+        Timber.w("UPnP select: Seek to track %d", currentIndex + 1)
+        transport.seekToTrack(currentIndex + 1)
+        Timber.w("UPnP select: Play")
+        transport.play()
+        Timber.w("UPnP select: initial done; backgrounding remainder")
+        val remaining = queue.drop(initialEnd)
+        if (remaining.isNotEmpty()) {
+            scope.launch { extendQueueOnSonos(transport, route, remaining, initialEnd) }
+        }
+    }
+
+    /**
+     * Background-append tracks after activation. Runs concurrently with
+     * Sonos playback. Cancels if the user disconnects from this route
+     * (active.routeId changes or becomes null). Tolerates individual
+     * AddURIToQueue failures — log and continue so some tracks loaded
+     * is better than zero tracks loaded.
+     */
+    private suspend fun extendQueueOnSonos(
+        transport: AVTransportClient,
+        route: OutputRoute,
+        tracks: List<TrackRef>,
+        startPosition: Int,
+    ) {
+        Timber.w(
+            "UPnP extend: appending %d tracks starting at position %d",
+            tracks.size, startPosition + 1,
+        )
+        var consecutiveFailures = 0
+        var succeeded = 0
+        var aborted = false
+        for ((i, ref) in tracks.withIndex()) {
+            if (aborted) break
+            if (activeUpnpHolder.active.value?.routeId != route.id) {
+                Timber.w("UPnP extend: cancelled at offset %d (route changed)", i)
+                aborted = true
+            } else {
+                val outcome = runCatching {
+                    val token = streamTokens.mint(ref.id)
+                    transport.addURIToQueue(
+                        uri = token.url,
+                        mime = token.mime,
+                        title = token.title,
+                        enqueuedURIPosition = startPosition + i + 1,
+                    )
+                }
+                if (outcome.isSuccess) {
+                    consecutiveFailures = 0
+                    succeeded += 1
+                    // Throttle the burst so we don't tickle Sonos's burst-add
+                    // rejection -- logcat 2026-06-04 showed 33 consecutive
+                    // failures clustered at ~10ms intervals once offset 39 was
+                    // reached, which looks like a rate-limit kicking in. The
+                    // delay is small enough that extending 100 tracks adds
+                    // only ~5s to background work that's already async.
+                    delay(EXTEND_THROTTLE_MS)
+                } else {
+                    consecutiveFailures += 1
+                    val e = outcome.exceptionOrNull()
+                    val detail = (e as? SoapFaultException)?.let {
+                        "code=${it.code} desc=${it.description}"
+                    } ?: e?.message
+                    Timber.w(e, "UPnP extend: append failed at offset %d -- %s", i, detail)
+                    if (consecutiveFailures >= EXTEND_ABORT_AFTER_FAILURES) {
+                        Timber.w(
+                            "UPnP extend: aborting after %d consecutive failures",
+                            consecutiveFailures,
+                        )
+                        aborted = true
+                    }
+                }
+            }
+        }
+        Timber.w("UPnP extend: done (%d / %d appended)", succeeded, tracks.size)
+    }
+
+    private fun renderingClientFor(routeId: String): RenderingControlClient? {
+        val rcUrl = upnpDiscovery.routes.value
+            .firstOrNull { it.id == routeId }
+            ?.renderingControlUrl ?: return null
+        return RenderingControlClient(SoapClient(okHttp), rcUrl)
+    }
+
+    private fun refresh() {
+        systemRoutesInternal.value = snapshotFromRouter()
+    }
+
+    private fun snapshotFromRouter(): RouteSnapshot {
+        val all = mediaRouter.routes
+            .filter { it.matchesSelector(selector) }
+            .map { OutputRoute.fromRouteInfo(it) }
+        val current = OutputRoute.fromRouteInfo(mediaRouter.selectedRoute)
+        return RouteSnapshot(current = current, available = sortRoutes(all))
+    }
+
+    /**
+     * BuiltIn "Phone speaker" pinned first; everything else
+     * alphabetical. Selection state is conveyed by the radio button
+     * indicator in the picker row, not by sort order.
+     */
+    private fun sortRoutes(all: List<OutputRoute>): List<OutputRoute> {
+        val (builtIn, rest) = all.partition { it.kind == OutputRoute.Kind.BuiltIn }
+        return builtIn + rest.sortedBy { it.name.lowercase() }
+    }
+
+    private companion object {
+        const val EXTEND_ABORT_AFTER_FAILURES = 3
+        const val EXTEND_THROTTLE_MS = 50L
+
+        // 5 minutes of continuous non-playing on a UPnP route before we
+        // revert to the phone speaker, so a stale Sonos selection can't make
+        // a later "tap play" do nothing.
+        const val IDLE_REVERT_MS = 5 * 60 * 1000L
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/OutputPickerSheet.kt

@@ -0,0 +1,211 @@
+package com.fabledsword.minstrel.player.output
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.ModalBottomSheet
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.rememberModalBottomSheetState
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import com.composables.icons.lucide.Circle
+import com.composables.icons.lucide.CircleCheck
+import com.composables.icons.lucide.Lucide
+import com.composables.icons.lucide.Settings
+import com.composables.icons.lucide.WifiOff
+
+/**
+ * Material 3 ModalBottomSheet listing the available output routes.
+ * Tap a row to select + dismiss. Selected route shows the accent
+ * CircleCheck; others show an empty Circle. Long route names
+ * truncate cleanly via maxLines = 2 + Ellipsis.
+ *
+ * Two footer hints, each driven by a flag the host screen owns:
+ *  - [permissionDenied] — NowPlayingScreen owns the BLUETOOTH_CONNECT
+ *    request flow and sets this true on denial so the user sees the
+ *    "pair in Settings" affordance.
+ *  - [noUpnpDiscovered] — set true when the picker has been open for
+ *    a few seconds and no UPnP renderers have arrived; surfaces the
+ *    "router may be blocking multicast" hint. Defaults to false so
+ *    existing call sites that haven't wired the discovery-timing
+ *    logic continue to render without the hint.
+ *
+ * Keeping the hint flags external preserves this composable's
+ * focus-on-rendering shape.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun OutputPickerSheet(
+    snapshot: RouteSnapshot,
+    permissionDenied: Boolean,
+    onRouteSelected: (OutputRoute) -> Unit,
+    onDismiss: () -> Unit,
+    noUpnpDiscovered: Boolean = false,
+) {
+    val sheetState = rememberModalBottomSheetState()
+    ModalBottomSheet(
+        onDismissRequest = onDismiss,
+        sheetState = sheetState,
+    ) {
+        Column(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 24.dp, vertical = 8.dp),
+            verticalArrangement = Arrangement.spacedBy(4.dp),
+        ) {
+            Text(
+                text = "Output",
+                style = MaterialTheme.typography.titleMedium,
+                color = MaterialTheme.colorScheme.onSurface,
+                modifier = Modifier.padding(vertical = 8.dp),
+            )
+            LazyColumn(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .heightIn(max = ROUTE_LIST_MAX_HEIGHT_DP.dp),
+                verticalArrangement = Arrangement.spacedBy(4.dp),
+            ) {
+                items(items = snapshot.available, key = { it.id }) { route ->
+                    RouteRow(
+                        route = route,
+                        isSelected = route.id == snapshot.current.id,
+                        onClick = { onRouteSelected(route) },
+                    )
+                }
+            }
+            if (permissionDenied) {
+                PermissionHintRow()
+            }
+            if (noUpnpDiscovered) {
+                MulticastHintRow()
+            }
+        }
+    }
+}
+
+@Composable
+private fun RouteRow(
+    route: OutputRoute,
+    isSelected: Boolean,
+    onClick: () -> Unit,
+) {
+    val tint = if (isSelected) {
+        MaterialTheme.colorScheme.primary
+    } else {
+        MaterialTheme.colorScheme.onSurfaceVariant
+    }
+    Surface(
+        onClick = onClick,
+        color = MaterialTheme.colorScheme.surface,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(vertical = 12.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(16.dp),
+        ) {
+            Icon(
+                imageVector = iconFor(route.kind),
+                contentDescription = null,
+                tint = tint,
+                modifier = Modifier.size(ROW_ICON_DP.dp),
+            )
+            Column(modifier = Modifier.weight(1f)) {
+                Text(
+                    text = route.name,
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = MaterialTheme.colorScheme.onSurface,
+                    maxLines = 2,
+                    overflow = TextOverflow.Ellipsis,
+                )
+                val subtitle = route.description ?: defaultSubtitle(route)
+                Text(
+                    text = subtitle,
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            }
+            Icon(
+                imageVector = if (isSelected) Lucide.CircleCheck else Lucide.Circle,
+                contentDescription = if (isSelected) "Selected" else "Not selected",
+                tint = tint,
+                modifier = Modifier.size(ROW_ICON_DP.dp),
+            )
+        }
+    }
+}
+
+@Composable
+private fun PermissionHintRow() {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(vertical = 12.dp),
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(12.dp),
+    ) {
+        Icon(
+            imageVector = Lucide.Settings,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(HINT_ICON_DP.dp),
+        )
+        Text(
+            text = "Pair a Bluetooth device in Settings to see it here.",
+            style = MaterialTheme.typography.bodySmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+    }
+}
+
+@Composable
+private fun MulticastHintRow() {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(vertical = 12.dp),
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(12.dp),
+    ) {
+        Icon(
+            imageVector = Lucide.WifiOff,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(HINT_ICON_DP.dp),
+        )
+        Text(
+            text = "Your router may be blocking multicast discovery.",
+            style = MaterialTheme.typography.bodySmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+    }
+}
+
+private fun defaultSubtitle(route: OutputRoute): String = when (route.kind) {
+    OutputRoute.Kind.BuiltIn -> "Phone speaker"
+    OutputRoute.Kind.Wired -> "Wired"
+    OutputRoute.Kind.Bluetooth -> if (route.isConnected) "Connected" else "Available"
+    OutputRoute.Kind.Cast -> "Cast"
+    OutputRoute.Kind.Other -> "Available"
+}
+
+private const val ROW_ICON_DP = 24
+private const val HINT_ICON_DP = 20
+private const val ROUTE_LIST_MAX_HEIGHT_DP = 400

android/app/src/main/java/com/fabledsword/minstrel/player/output/OutputPickerViewModel.kt

@@ -0,0 +1,64 @@
+package com.fabledsword.minstrel.player.output
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.stateIn
+import javax.inject.Inject
+
+/**
+ * NowPlaying-scoped projection over [OutputPickerController]. The
+ * controller is the long-lived Hilt singleton (its MediaRouter
+ * callback must not churn with screen lifecycle); this ViewModel is
+ * a thin lens over its [OutputPickerController.routesState] Flow
+ * plus the sheet's visibility state.
+ *
+ * Sheet open/close are forwarded to the controller's discovery
+ * toggle so active MediaRouter discovery only runs while the sheet
+ * is actually visible.
+ */
+@HiltViewModel
+class OutputPickerViewModel @Inject constructor(
+    private val controller: OutputPickerController,
+    private val activeUpnpHolder: ActiveUpnpHolder,
+) : ViewModel() {
+
+    val routes: StateFlow<RouteSnapshot> = controller.routesState
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(STOP_TIMEOUT_MS),
+            initialValue = controller.routesState.value,
+        )
+
+    val activeUpnp: StateFlow<ActiveUpnp?> = activeUpnpHolder.active
+        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(STOP_TIMEOUT_MS), null)
+
+    private val sheetVisibleInternal = MutableStateFlow(false)
+    val sheetVisible: StateFlow<Boolean> = sheetVisibleInternal.asStateFlow()
+
+    fun onChipTapped() {
+        sheetVisibleInternal.value = true
+        controller.upgradeDiscovery()
+    }
+
+    fun onSheetDismissed() {
+        sheetVisibleInternal.value = false
+        controller.downgradeDiscovery()
+    }
+
+    fun onRouteSelected(route: OutputRoute) {
+        controller.select(route)
+        sheetVisibleInternal.value = false
+        controller.downgradeDiscovery()
+    }
+
+    private companion object {
+        // SharingStarted timeout so quick screen-orientation changes
+        // don't tear down + re-subscribe the controller's Flow.
+        const val STOP_TIMEOUT_MS = 5_000L
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/OutputRoute.kt

@@ -0,0 +1,103 @@
+package com.fabledsword.minstrel.player.output
+
+import androidx.mediarouter.media.MediaRouter
+import com.fabledsword.minstrel.player.output.upnp.UpnpRoute
+
+/**
+ * Narrow domain model for an audio output route. Independent of
+ * [MediaRouter.RouteInfo] so the picker UI can preview without an
+ * Android framework presence (RouteInfo can't be constructed in
+ * JVM tests, mirroring the LikeMediaCallback constraint).
+ *
+ * The [protocol] field is a forward-compatibility hook for the
+ * UPnP / DLNA / Sonos / Cast slice (scope captured in
+ * docs/superpowers/specs/2026-06-03-android-output-picker-upnp-scope.md).
+ * THIS slice always sets `protocol = SYSTEM` — the system-route
+ * categories MediaRouter surfaces (built-in / wired / Bluetooth).
+ */
+data class OutputRoute(
+    val id: String,
+    val name: String,
+    val description: String?,
+    val kind: Kind,
+    val protocol: Protocol,
+    val isConnected: Boolean,
+) {
+    enum class Kind { BuiltIn, Wired, Bluetooth, Cast, Other }
+
+    enum class Protocol {
+        /** System-managed routes — built-in speaker, wired, Bluetooth. */
+        SYSTEM,
+
+        /** Generic UPnP / DLNA renderers — reserved for the next slice. */
+        UPNP,
+
+        /** Chromecast via the Cast SDK — reserved for a later slice. */
+        CAST,
+
+        /** Sonos via the Sonos extension on top of UPnP — reserved. */
+        SONOS,
+    }
+
+    companion object {
+        /**
+         * Lift a MediaRouter [route] into the domain model. Kind is
+         * inferred from [MediaRouter.RouteInfo.getDeviceType]; unknown
+         * device types fall through to [Kind.Other]. The
+         * `connectionState` proxy is good enough for the chip's
+         * "Connected"/"Available" subtitle.
+         */
+        fun fromRouteInfo(route: MediaRouter.RouteInfo): OutputRoute {
+            val kind = when (route.deviceType) {
+                MediaRouter.RouteInfo.DEVICE_TYPE_BUILTIN_SPEAKER -> Kind.BuiltIn
+                MediaRouter.RouteInfo.DEVICE_TYPE_WIRED_HEADSET,
+                MediaRouter.RouteInfo.DEVICE_TYPE_WIRED_HEADPHONES,
+                -> Kind.Wired
+                MediaRouter.RouteInfo.DEVICE_TYPE_BLUETOOTH_A2DP -> Kind.Bluetooth
+                MediaRouter.RouteInfo.DEVICE_TYPE_TV -> Kind.Other
+                MediaRouter.RouteInfo.DEVICE_TYPE_SPEAKER -> Kind.Other
+                else -> Kind.Other
+            }
+            val connected =
+                route.connectionState == MediaRouter.RouteInfo.CONNECTION_STATE_CONNECTED
+            return OutputRoute(
+                id = route.id,
+                name = route.name,
+                description = route.description,
+                kind = kind,
+                protocol = Protocol.SYSTEM,
+                isConnected = connected,
+            )
+        }
+
+        /**
+         * Lift a discovered UPnP renderer into the picker's domain
+         * model. Used by the UPnP discovery controller to merge
+         * network speakers into the same `OutputPickerController`
+         * routes stream the system routes come through.
+         *
+         * `isConnected = false` because UPnP devices have no
+         * MediaRouter connection-state concept — they're always
+         * "available" on the LAN, and the picker's selected-route
+         * rendering handles the "currently playing" indicator.
+         *
+         * Subtitle is `manufacturer modelName` joined by a single
+         * space, falling back to "Network speaker" when both fields
+         * are blank.
+         */
+        fun fromUpnpRoute(route: UpnpRoute): OutputRoute {
+            val description = listOfNotNull(
+                route.manufacturer.takeIf { it.isNotBlank() },
+                route.modelName.takeIf { it.isNotBlank() },
+            ).joinToString(" ").ifBlank { "Network speaker" }
+            return OutputRoute(
+                id = route.id,
+                name = route.name,
+                description = description,
+                kind = Kind.Other,
+                protocol = Protocol.UPNP,
+                isConnected = false,
+            )
+        }
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/AVTransportClient.kt

@@ -0,0 +1,296 @@
+package com.fabledsword.minstrel.player.output.upnp
+
+import okhttp3.HttpUrl
+
+/**
+ * High-level wrapper for the UPnP AVTransport service.
+ * Covers SetAVTransportURI / Play / Pause / Stop / Seek /
+ * GetPositionInfo / GetTransportInfo / queue management
+ * (RemoveAllTracksFromQueue, AddURIToQueue, Next, Previous, SeekToTrack).
+ */
+// One method per AVTransport SOAP verb; splitting would obscure the 1:1 protocol mapping.
+@Suppress("TooManyFunctions")
+class AVTransportClient(
+    private val soap: SoapClient,
+    private val controlUrl: HttpUrl,
+) {
+    suspend fun setAVTransportURI(uri: String, metadata: String = "") {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "SetAVTransportURI",
+            args = mapOf(
+                "InstanceID" to "0",
+                "CurrentURI" to uri,
+                "CurrentURIMetaData" to metadata,
+            ),
+        )
+    }
+
+    /**
+     * Convenience overload that builds DIDL-Lite metadata around [uri]
+     * + [mime] + [title] and forwards to [setAVTransportURI]. Sonos
+     * rejects empty DIDL with vendor error 1023; this constructs the
+     * minimal-but-Sonos-acceptable shape:
+     *   <DIDL-Lite>
+     *     <item id="0" parentID="-1" restricted="1">
+     *       <dc:title>...</dc:title>
+     *       <upnp:class>object.item.audioItem.musicTrack</upnp:class>
+     *       <res protocolInfo="http-get:*:<mime>:*">...</res>
+     *     </item>
+     *   </DIDL-Lite>
+     * Generic UPnP renderers tolerate this shape too — there's no
+     * downside to always sending it. Title falls back to "Minstrel"
+     * when the caller doesn't supply one.
+     */
+    suspend fun setAVTransportURIWithMetadata(uri: String, mime: String, title: String) {
+        val safeTitle = title.ifBlank { "Minstrel" }
+        setAVTransportURI(uri, buildDidlLite(uri, mime, safeTitle))
+    }
+
+    /**
+     * Remove all tracks from the renderer's queue. UPnP action name is
+     * `RemoveAllTracksFromQueue`. Used at activation time to clear out any
+     * leftover queue from prior sessions before loading our local queue.
+     */
+    suspend fun removeAllTracksFromQueue() {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "RemoveAllTracksFromQueue",
+            args = mapOf("InstanceID" to "0"),
+        )
+    }
+
+    /**
+     * Remove a contiguous range of tracks from the renderer's native queue.
+     * Sonos-specific extension to AVTransport; `UpdateID=0` skips the queue-
+     * version check so this works without first calling GetQueue to learn
+     * the current update id.
+     *
+     * [startingIndex] is 1-based per Sonos convention; [numberOfTracks] is
+     * the count to remove. Used by OutputPickerController's incremental
+     * queue resync path (radio-append: remove tail, then AddURIToQueue
+     * the new items).
+     */
+    suspend fun removeTrackRangeFromQueue(startingIndex: Int, numberOfTracks: Int) {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "RemoveTrackRangeFromQueue",
+            args = mapOf(
+                "InstanceID" to "0",
+                "UpdateID" to "0",
+                "StartingIndex" to startingIndex.toString(),
+                "NumberOfTracks" to numberOfTracks.toString(),
+            ),
+        )
+    }
+
+    /**
+     * Append a track to the renderer's queue. Sonos returns the assigned
+     * track number + new total queue length in the response, but we don't
+     * read those (we know our intended position). DIDL-Lite metadata is
+     * required; reuses the same shape as [setAVTransportURIWithMetadata].
+     *
+     * [enqueuedURIPosition] is 1-based; 0 means "append to end" per UPnP.
+     * Our caller passes 1, 2, 3, ... to ensure stable order.
+     */
+    suspend fun addURIToQueue(
+        uri: String,
+        mime: String,
+        title: String,
+        enqueuedURIPosition: Int = 0,
+    ) {
+        val safeTitle = title.ifBlank { "Minstrel" }
+        val didl = buildDidlLite(uri, mime, safeTitle)
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "AddURIToQueue",
+            args = mapOf(
+                "InstanceID" to "0",
+                "EnqueuedURI" to uri,
+                "EnqueuedURIMetaData" to didl,
+                "DesiredFirstTrackNumberEnqueued" to enqueuedURIPosition.toString(),
+                "EnqueueAsNext" to "0",
+            ),
+        )
+    }
+
+    /** Skip to the next track in the renderer's queue. */
+    suspend fun next() {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "Next",
+            args = mapOf("InstanceID" to "0"),
+        )
+    }
+
+    /** Skip to the previous track in the renderer's queue. */
+    suspend fun previous() {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "Previous",
+            args = mapOf("InstanceID" to "0"),
+        )
+    }
+
+    /**
+     * Seek to a specific track in the queue. UPnP Seek unit "TRACK_NR";
+     * target is the 1-based track index. Separate from the existing
+     * [seek] which uses unit REL_TIME for position-within-track.
+     */
+    suspend fun seekToTrack(trackNumber: Int) {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "Seek",
+            args = mapOf(
+                "InstanceID" to "0",
+                "Unit" to "TRACK_NR",
+                "Target" to trackNumber.toString(),
+            ),
+        )
+    }
+
+    suspend fun play() {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "Play",
+            args = mapOf("InstanceID" to "0", "Speed" to "1"),
+        )
+    }
+
+    suspend fun pause() {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "Pause",
+            args = mapOf("InstanceID" to "0"),
+        )
+    }
+
+    suspend fun stop() {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "Stop",
+            args = mapOf("InstanceID" to "0"),
+        )
+    }
+
+    suspend fun seek(positionMs: Long) {
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "Seek",
+            args = mapOf(
+                "InstanceID" to "0",
+                "Unit" to "REL_TIME",
+                "Target" to formatHhMmSs(positionMs),
+            ),
+        )
+    }
+
+    suspend fun getPositionInfo(): PositionInfo {
+        val result = soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "GetPositionInfo",
+            args = mapOf("InstanceID" to "0"),
+        )
+        return PositionInfo(
+            track = result["Track"]?.toIntOrNull() ?: 0,
+            trackUri = result["TrackURI"].orEmpty(),
+            relTimeMs = parseHhMmSs(result["RelTime"].orEmpty()),
+            trackDurationMs = parseHhMmSs(result["TrackDuration"].orEmpty()),
+        )
+    }
+
+    suspend fun getTransportInfo(): TransportInfo {
+        val result = soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "GetTransportInfo",
+            args = mapOf("InstanceID" to "0"),
+        )
+        val state = when (result["CurrentTransportState"]) {
+            "PLAYING" -> TransportState.PLAYING
+            "PAUSED_PLAYBACK" -> TransportState.PAUSED
+            "STOPPED" -> TransportState.STOPPED
+            "TRANSITIONING" -> TransportState.TRANSITIONING
+            else -> TransportState.UNKNOWN
+        }
+        return TransportInfo(state)
+    }
+
+    private fun buildDidlLite(uri: String, mime: String, title: String): String {
+        // Sonos requires (a) the rinconnetworks namespace declared on
+        // <DIDL-Lite> even if we don't use Rincon elements directly, and
+        // (b) a <desc id="cdudn"> element identifying the URI as an
+        // external (non-Sonos-library) source. Without those, Sonos
+        // discards our metadata content and regenerates its own with
+        // class=object.item and the URL query string as the title
+        // (logcat 2026-06-04 confirmed). Match SoCo's pattern.
+        val safeTitle = title.ifBlank { "Minstrel" }
+        return buildString {
+            append("<DIDL-Lite ")
+            append("xmlns=\"urn:schemas-upnp-org:metadata-1-0/DIDL-Lite/\" ")
+            append("xmlns:dc=\"http://purl.org/dc/elements/1.1/\" ")
+            append("xmlns:upnp=\"urn:schemas-upnp-org:metadata-1-0/upnp/\" ")
+            append("xmlns:r=\"urn:schemas-rinconnetworks-com:metadata-1-0/\">")
+            append("<item id=\"-1\" parentID=\"-1\" restricted=\"true\">")
+            append("<dc:title>").append(xmlEscape(safeTitle)).append("</dc:title>")
+            append("<upnp:class>object.item.audioItem.musicTrack</upnp:class>")
+            append("<res protocolInfo=\"http-get:*:").append(xmlEscape(mime))
+            append(":*\">").append(xmlEscape(uri)).append("</res>")
+            append("<desc id=\"cdudn\" ")
+            append("nameSpace=\"urn:schemas-rinconnetworks-com:metadata-1-0/\">")
+            append("RINCON_AssociatedZPUDN")
+            append("</desc>")
+            append("</item>")
+            append("</DIDL-Lite>")
+        }
+    }
+
+    private fun formatHhMmSs(positionMs: Long): String {
+        val totalSec = (positionMs / MILLIS_PER_SECOND).coerceAtLeast(0)
+        val h = totalSec / SECONDS_PER_HOUR
+        val m = (totalSec % SECONDS_PER_HOUR) / SECONDS_PER_MINUTE
+        val s = totalSec % SECONDS_PER_MINUTE
+        return "%d:%02d:%02d".format(h, m, s)
+    }
+
+    private fun parseHhMmSs(raw: String): Long {
+        val parts = raw.split(':').mapNotNull { it.trim().toLongOrNull() }
+        return if (parts.size == EXPECTED_HMS_PARTS) {
+            val (h, m, s) = parts
+            ((h * SECONDS_PER_HOUR) + (m * SECONDS_PER_MINUTE) + s) * MILLIS_PER_SECOND
+        } else {
+            0L
+        }
+    }
+
+    private companion object {
+        const val SERVICE_TYPE = "urn:schemas-upnp-org:service:AVTransport:1"
+        const val MILLIS_PER_SECOND = 1000L
+        const val SECONDS_PER_MINUTE = 60L
+        const val SECONDS_PER_HOUR = 3600L
+        const val EXPECTED_HMS_PARTS = 3
+    }
+}
+
+data class PositionInfo(
+    val track: Int,
+    val trackUri: String,
+    val relTimeMs: Long,
+    val trackDurationMs: Long,
+)
+
+enum class TransportState { PLAYING, PAUSED, STOPPED, TRANSITIONING, UNKNOWN }
+
+data class TransportInfo(val state: TransportState)

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/DeviceDescription.kt

@@ -0,0 +1,128 @@
+package com.fabledsword.minstrel.player.output.upnp
+
+import okhttp3.HttpUrl
+import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
+import org.xmlpull.v1.XmlPullParser
+import org.xmlpull.v1.XmlPullParserFactory
+
+/**
+ * Pull-parsed UPnP device description (the XML returned from a
+ * discovered LOCATION URL). Carries the bits we actually need for
+ * the picker: friendlyName / manufacturer / modelName for display,
+ * AVTransport + RenderingControl control URLs for command dispatch.
+ *
+ * Filtered to MediaRenderer-capable devices — anything without an
+ * AVTransport service control URL is dropped by [parse] returning
+ * null (we can't make it play).
+ */
+data class DeviceDescription(
+    val udn: String,
+    val friendlyName: String,
+    val manufacturer: String,
+    val modelName: String,
+    val avTransportControlUrl: HttpUrl,
+    val renderingControlUrl: HttpUrl?,
+    val zoneGroupTopologyControlUrl: HttpUrl? = null,
+) {
+    companion object {
+        private const val AVT_SERVICE_TYPE = "urn:schemas-upnp-org:service:AVTransport:1"
+        private const val RC_SERVICE_TYPE = "urn:schemas-upnp-org:service:RenderingControl:1"
+        private const val ZGT_SERVICE_TYPE = "urn:schemas-upnp-org:service:ZoneGroupTopology:1"
+
+        private const val TAG_SERVICE = "service"
+        private const val TAG_UDN = "UDN"
+        private const val TAG_FRIENDLY_NAME = "friendlyName"
+        private const val TAG_MANUFACTURER = "manufacturer"
+        private const val TAG_MODEL_NAME = "modelName"
+        private const val TAG_SERVICE_TYPE = "serviceType"
+        private const val TAG_CONTROL_URL = "controlURL"
+
+        /**
+         * Parse [xml] (the body fetched from the SSDP LOCATION URL),
+         * resolving relative service control URLs against [base].
+         * Returns null when AVTransport is missing — we have no way
+         * to control the device without it.
+         */
+        fun parse(xml: String, base: HttpUrl): DeviceDescription? {
+            val parser = XmlPullParserFactory.newInstance().newPullParser().apply {
+                setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true)
+                setInput(xml.reader())
+            }
+            val acc = ParseState()
+            while (parser.eventType != XmlPullParser.END_DOCUMENT) {
+                handleEvent(parser, acc, base)
+                parser.next()
+            }
+            val avt = acc.avtControlUrl ?: return null
+            return DeviceDescription(
+                udn = acc.udn,
+                friendlyName = acc.friendlyName,
+                manufacturer = acc.manufacturer,
+                modelName = acc.modelName,
+                avTransportControlUrl = avt,
+                renderingControlUrl = acc.rcControlUrl,
+                zoneGroupTopologyControlUrl = acc.zgtControlUrl,
+            )
+        }
+
+        private fun handleEvent(parser: XmlPullParser, acc: ParseState, base: HttpUrl) {
+            when (parser.eventType) {
+                XmlPullParser.START_TAG -> handleStartTag(parser, acc)
+                XmlPullParser.END_TAG -> handleEndTag(parser, acc, base)
+                else -> Unit
+            }
+        }
+
+        private fun handleStartTag(parser: XmlPullParser, acc: ParseState) {
+            when (parser.name) {
+                TAG_SERVICE -> {
+                    acc.inService = true
+                    acc.serviceType = ""
+                    acc.serviceControlUrl = ""
+                }
+                TAG_UDN -> acc.udn = parser.nextTextSafe()
+                TAG_FRIENDLY_NAME -> acc.friendlyName = parser.nextTextSafe()
+                TAG_MANUFACTURER -> acc.manufacturer = parser.nextTextSafe()
+                TAG_MODEL_NAME -> acc.modelName = parser.nextTextSafe()
+                TAG_SERVICE_TYPE -> if (acc.inService) acc.serviceType = parser.nextTextSafe()
+                TAG_CONTROL_URL -> if (acc.inService) acc.serviceControlUrl = parser.nextTextSafe()
+            }
+        }
+
+        private fun handleEndTag(parser: XmlPullParser, acc: ParseState, base: HttpUrl) {
+            if (parser.name != TAG_SERVICE) return
+            val resolved = resolveControlUrl(base, acc.serviceControlUrl)
+            when (acc.serviceType) {
+                AVT_SERVICE_TYPE -> acc.avtControlUrl = resolved
+                RC_SERVICE_TYPE -> acc.rcControlUrl = resolved
+                ZGT_SERVICE_TYPE -> acc.zgtControlUrl = resolved
+            }
+            acc.inService = false
+        }
+
+        private fun resolveControlUrl(base: HttpUrl, path: String): HttpUrl? {
+            if (path.isBlank()) return null
+            return path.toHttpUrlOrNull() ?: base.resolve(path)
+        }
+
+        private fun XmlPullParser.nextTextSafe(): String =
+            runCatching { nextText() }.getOrDefault("")
+    }
+
+    /**
+     * Mutable accumulator used during pull-parsing. Lives only for the
+     * duration of one [parse] call.
+     */
+    private class ParseState {
+        var udn: String = ""
+        var friendlyName: String = ""
+        var manufacturer: String = ""
+        var modelName: String = ""
+        var avtControlUrl: HttpUrl? = null
+        var rcControlUrl: HttpUrl? = null
+        var zgtControlUrl: HttpUrl? = null
+        var inService: Boolean = false
+        var serviceType: String = ""
+        var serviceControlUrl: String = ""
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/RenderingControlClient.kt

@@ -0,0 +1,44 @@
+package com.fabledsword.minstrel.player.output.upnp
+
+import okhttp3.HttpUrl
+
+/**
+ * RenderingControl service wrapper for hardware-volume routing while a
+ * UPnP route is active. GetVolume seeds an in-memory cache; SetVolume
+ * is invoked by NowPlayingScreen's volume-key interceptor. Clamps to
+ * the UPnP-standard 0..100 range.
+ */
+class RenderingControlClient(
+    private val soap: SoapClient,
+    private val controlUrl: HttpUrl,
+) {
+    suspend fun getVolume(channel: String = "Master"): Int {
+        val args = soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "GetVolume",
+            args = mapOf("InstanceID" to "0", "Channel" to channel),
+        )
+        return args["CurrentVolume"]?.toIntOrNull() ?: 0
+    }
+
+    suspend fun setVolume(volume: Int, channel: String = "Master") {
+        val clamped = volume.coerceIn(VOLUME_MIN, VOLUME_MAX)
+        soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "SetVolume",
+            args = mapOf(
+                "InstanceID" to "0",
+                "Channel" to channel,
+                "DesiredVolume" to clamped.toString(),
+            ),
+        )
+    }
+
+    private companion object {
+        const val SERVICE_TYPE = "urn:schemas-upnp-org:service:RenderingControl:1"
+        const val VOLUME_MIN = 0
+        const val VOLUME_MAX = 100
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/SoapClient.kt

@@ -0,0 +1,230 @@
+package com.fabledsword.minstrel.player.output.upnp
+
+import java.util.concurrent.atomic.AtomicInteger
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import okhttp3.HttpUrl
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okhttp3.RequestBody.Companion.toRequestBody
+import org.xmlpull.v1.XmlPullParser
+import org.xmlpull.v1.XmlPullParserFactory
+import timber.log.Timber
+
+/**
+ * Minimal SOAP/UPnP envelope builder + POST. Hand-rolled rather than
+ * pulled in via jupnp; we control every line and integrate cleanly
+ * with the app's OkHttpClient (shared connection pool, timeouts).
+ *
+ * Builds the standard SOAP 1.1 envelope, POSTs with the required
+ * SOAPACTION + Content-Type headers, returns the parsed
+ * `<action>Response` element as a Map<String, String> (UPnP responses
+ * are flat string maps).
+ *
+ * Throws [SoapFaultException] on a `<s:Fault>` response (the UPnP
+ * device's way of saying "I rejected your request"). Other transport
+ * errors propagate as IOException.
+ */
+class SoapClient(
+    private val okHttp: OkHttpClient,
+    private val onRawResponse: ((action: String, body: String) -> Unit)? = null,
+) {
+    suspend fun call(
+        controlUrl: HttpUrl,
+        serviceType: String,
+        action: String,
+        args: Map<String, String> = emptyMap(),
+    ): Map<String, String> = withContext(Dispatchers.IO) {
+        val envelope = buildEnvelope(serviceType, action, args)
+        val request = Request.Builder()
+            .url(controlUrl)
+            .post(envelope.toRequestBody(null))
+            .header("Content-Type", SOAP_CONTENT_TYPE)
+            .header("SOAPACTION", "\"$serviceType#$action\"")
+            .build()
+        okHttp.newCall(request).execute().use { response ->
+            val body = response.body?.string().orEmpty()
+            onRawResponse?.invoke(action, body)
+            if (!response.isSuccessful) {
+                throw SoapFaultException(faultCodeOf(body), faultDescriptionOf(body))
+            }
+            parseResponseArgs(body, action)
+        }
+    }
+
+    private fun buildEnvelope(
+        serviceType: String,
+        action: String,
+        args: Map<String, String>,
+    ): String = buildString {
+        append("<?xml version=\"1.0\"?>")
+        append("<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\"")
+        append(" s:encodingStyle=\"http://schemas.xmlsoap.org/soap/encoding/\">")
+        append("<s:Body>")
+        append("<u:").append(action)
+        append(" xmlns:u=\"").append(serviceType).append("\">")
+        args.forEach { (k, v) ->
+            append("<").append(k).append(">")
+            append(xmlEscape(v))
+            append("</").append(k).append(">")
+        }
+        append("</u:").append(action).append(">")
+        append("</s:Body>")
+        append("</s:Envelope>")
+    }
+
+    private fun parseResponseArgs(body: String, action: String): Map<String, String> {
+        val parser = XmlPullParserFactory.newInstance().newPullParser().apply {
+            setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true)
+            setInput(body.reader())
+        }
+        val responseTag = "${action}Response"
+        val args = mutableMapOf<String, String>()
+        var inResponse = false
+        while (parser.eventType != XmlPullParser.END_DOCUMENT) {
+            inResponse = handleParserEvent(parser, responseTag, inResponse, args)
+            parser.next()
+        }
+        return args
+    }
+
+    private fun handleParserEvent(
+        parser: XmlPullParser,
+        responseTag: String,
+        inResponse: Boolean,
+        args: MutableMap<String, String>,
+    ): Boolean = when (parser.eventType) {
+        XmlPullParser.START_TAG -> {
+            if (parser.name == responseTag) {
+                true
+            } else {
+                if (inResponse) {
+                    val name = parser.name
+                    val text = readElementContent(parser, name)
+                    args[name] = text
+                }
+                inResponse
+            }
+        }
+        XmlPullParser.END_TAG -> if (parser.name == responseTag) false else inResponse
+        else -> inResponse
+    }
+
+    /**
+     * Read the content of the currently-started element. Try nextText() first
+     * (works when the content is text -- escaped XML included). If that throws
+     * (because the content is nested elements), manually walk to the matching
+     * END_TAG, accumulating text and re-serializing child elements.
+     *
+     * Some Sonos firmware sends the GetZoneGroupState payload as nested XML
+     * elements without escaping; this fallback recovers that path.
+     */
+    private fun readElementContent(parser: XmlPullParser, tagName: String): String {
+        return runCatching { parser.nextText() }.getOrElse {
+            readUntilEndTag(parser, tagName)
+        }
+    }
+
+    private fun readUntilEndTag(parser: XmlPullParser, tagName: String): String {
+        val sb = StringBuilder()
+        var depth = 1
+        var done = false
+        while (!done && depth > 0) {
+            when (parser.next()) {
+                XmlPullParser.START_TAG -> {
+                    appendStartTag(sb, parser)
+                    depth += 1
+                }
+                XmlPullParser.END_TAG -> {
+                    depth -= 1
+                    if (depth == 0 && parser.name == tagName) {
+                        done = true
+                    } else {
+                        sb.append("</").append(parser.name).append('>')
+                    }
+                }
+                XmlPullParser.TEXT -> sb.append(parser.text.orEmpty())
+                XmlPullParser.END_DOCUMENT -> done = true
+                else -> Unit
+            }
+        }
+        return sb.toString()
+    }
+
+    private fun appendStartTag(sb: StringBuilder, parser: XmlPullParser) {
+        sb.append('<').append(parser.name)
+        for (i in 0 until parser.attributeCount) {
+            sb.append(' ')
+                .append(parser.getAttributeName(i))
+                .append("=\"")
+                .append(parser.getAttributeValue(i))
+                .append('"')
+        }
+        sb.append('>')
+    }
+
+    private fun faultCodeOf(body: String): String =
+        extractBetween(body, "<errorCode>", "</errorCode>") ?: "unknown"
+
+    private fun faultDescriptionOf(body: String): String =
+        extractBetween(body, "<errorDescription>", "</errorDescription>").orEmpty()
+
+    private fun extractBetween(body: String, open: String, close: String): String? {
+        val start = body.indexOf(open)
+        if (start < 0) return null
+        val contentStart = start + open.length
+        val end = body.indexOf(close, contentStart)
+        return if (end < 0) null else body.substring(contentStart, end)
+    }
+
+    private companion object {
+        const val SOAP_CONTENT_TYPE = "text/xml; charset=\"utf-8\""
+    }
+}
+
+/**
+ * Thrown when a UPnP device responds with `<s:Fault>` — typically wraps
+ * a UPnPError with `errorCode` + `errorDescription`. Code is preserved
+ * as a string (UPnP codes are numeric in spec but we don't constrain).
+ */
+class SoapFaultException(val code: String, val description: String) :
+    Exception("SOAP fault $code: $description")
+
+private const val MAX_DIAGNOSTIC_RESPONSES = 6  // 3 polls x 2 action types
+private const val MAX_BODY_LOG_CHARS = 2048
+
+/**
+ * Returns a [SoapClient] that logs the raw response body for the first
+ * [MAX_DIAGNOSTIC_RESPONSES] calls for actions in [DIAGNOSTIC_ACTIONS]
+ * (GetPositionInfo, GetTransportInfo, GetZoneGroupState). After that the
+ * callback is a no-op so there is no persistent log spam. Logged at WARN
+ * so release builds capture it without a separate log-level override.
+ */
+internal fun loggingSoapClient(okHttp: OkHttpClient, label: String): SoapClient {
+    val counter = AtomicInteger(0)
+    return SoapClient(okHttp) { action, body ->
+        if (action !in DIAGNOSTIC_ACTIONS) return@SoapClient
+        val n = counter.incrementAndGet()
+        if (n <= MAX_DIAGNOSTIC_RESPONSES) {
+            Timber.w(
+                "UPnP %s response #%d (%s): %s",
+                label, n, action,
+                body.take(MAX_BODY_LOG_CHARS),
+            )
+        }
+    }
+}
+
+private val DIAGNOSTIC_ACTIONS = setOf(
+    "GetPositionInfo",
+    "GetTransportInfo",
+    "GetZoneGroupState",
+)
+
+/** XML-escapes a string value for embedding as text content inside a SOAP envelope. */
+internal fun xmlEscape(v: String): String = v
+    .replace("&", "&amp;")
+    .replace("<", "&lt;")
+    .replace(">", "&gt;")
+    .replace("\"", "&quot;")
+    .replace("'", "&apos;")

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/SsdpDiscovery.kt

@@ -0,0 +1,126 @@
+package com.fabledsword.minstrel.player.output.upnp
+
+import android.content.Context
+import android.net.wifi.WifiManager
+import androidx.core.content.getSystemService
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.SharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
+import kotlinx.coroutines.isActive
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.net.DatagramPacket
+import java.net.InetAddress
+import java.net.MulticastSocket
+import java.nio.charset.StandardCharsets
+
+/**
+ * UDP multicast SSDP listener + M-SEARCH sender. Emits each discovery
+ * response's LOCATION URL on the [discoveries] SharedFlow; the
+ * `UpnpDiscoveryController` follows up by fetching + parsing each
+ * device description.
+ *
+ * Passive listen is always-on once [start] is called (NOTIFY packets
+ * speakers send when they boot / refresh). Active discovery (an
+ * explicit M-SEARCH request) is triggered by [requestActiveScan] —
+ * called when the picker sheet opens so newly-paired devices appear
+ * promptly.
+ *
+ * WifiManager.MulticastLock is held while the listener is running.
+ * Released by [stop] / cancellation of the parent scope.
+ */
+class SsdpDiscovery(
+    private val context: Context,
+) {
+    private val discoveriesInternal =
+        MutableSharedFlow<String>(extraBufferCapacity = DISCOVERY_BUFFER_CAPACITY)
+    val discoveries: SharedFlow<String> = discoveriesInternal.asSharedFlow()
+
+    private var multicastLock: WifiManager.MulticastLock? = null
+    private var socket: MulticastSocket? = null
+    private var listenJob: Job? = null
+
+    fun start(scope: CoroutineScope) {
+        if (listenJob != null) return
+        val wifi = context.getSystemService<WifiManager>() ?: return
+        multicastLock = wifi.createMulticastLock(MULTICAST_LOCK_TAG).apply {
+            setReferenceCounted(false)
+            acquire()
+        }
+        val sock = MulticastSocket(ANY_LOCAL_PORT).apply {
+            joinGroup(InetAddress.getByName(SSDP_MULTICAST_ADDR))
+        }
+        socket = sock
+        listenJob = scope.launch(Dispatchers.IO) {
+            val buf = ByteArray(SOCKET_READ_BUFFER_BYTES)
+            val packet = DatagramPacket(buf, buf.size)
+            while (isActive) {
+                runCatching { sock.receive(packet) }.onSuccess {
+                    val raw = String(packet.data, 0, packet.length, StandardCharsets.UTF_8)
+                    parseLocation(raw)?.let { discoveriesInternal.tryEmit(it) }
+                }
+            }
+        }
+    }
+
+    fun stop() {
+        listenJob?.cancel()
+        listenJob = null
+        runCatching { socket?.close() }
+        socket = null
+        runCatching { multicastLock?.release() }
+        multicastLock = null
+    }
+
+    /**
+     * Send an M-SEARCH packet asking for MediaRenderer:1 devices.
+     * Responses arrive on the listener socket and emit via
+     * [discoveries] as their LOCATION URL.
+     */
+    suspend fun requestActiveScan() = withContext(Dispatchers.IO) {
+        val sock = socket ?: return@withContext
+        val payload = buildMSearchPayload().toByteArray(StandardCharsets.UTF_8)
+        val packet = DatagramPacket(
+            payload,
+            payload.size,
+            InetAddress.getByName(SSDP_MULTICAST_ADDR),
+            SSDP_PORT,
+        )
+        runCatching { sock.send(packet) }
+        Unit
+    }
+
+    private fun buildMSearchPayload(): String = buildString {
+        append("M-SEARCH * HTTP/1.1\r\n")
+        append("HOST: ").append(SSDP_MULTICAST_ADDR).append(":").append(SSDP_PORT).append("\r\n")
+        append("MAN: \"ssdp:discover\"\r\n")
+        append("MX: ").append(MSEARCH_MX_SECONDS).append("\r\n")
+        append("ST: ").append(MEDIA_RENDERER_TARGET).append("\r\n")
+        append("\r\n")
+    }
+
+    private fun parseLocation(raw: String): String? {
+        raw.lineSequence().forEach { line ->
+            val trimmed = line.trim()
+            if (trimmed.startsWith(LOCATION_HEADER, ignoreCase = true)) {
+                return trimmed.substring(LOCATION_HEADER.length).trim()
+            }
+        }
+        return null
+    }
+
+    private companion object {
+        const val SSDP_MULTICAST_ADDR = "239.255.255.250"
+        const val SSDP_PORT = 1900
+        const val ANY_LOCAL_PORT = 0
+        const val SOCKET_READ_BUFFER_BYTES = 4096
+        const val DISCOVERY_BUFFER_CAPACITY = 32
+        const val MSEARCH_MX_SECONDS = 2
+        const val MULTICAST_LOCK_TAG = "minstrel.upnp.ssdp"
+        const val MEDIA_RENDERER_TARGET = "urn:schemas-upnp-org:device:MediaRenderer:1"
+        const val LOCATION_HEADER = "LOCATION:"
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/UpnpDiscoveryController.kt

@@ -0,0 +1,261 @@
+@file:Suppress("TooManyFunctions") // discovery + Sonos topology + transport-lookup density
+package com.fabledsword.minstrel.player.output.upnp
+
+import android.content.Context
+import com.fabledsword.minstrel.di.ApplicationScope
+import com.fabledsword.minstrel.player.output.upnp.sonos.SonosZoneGroup
+import com.fabledsword.minstrel.player.output.upnp.sonos.ZoneGroupTopologyClient
+import dagger.hilt.android.qualifiers.ApplicationContext
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import okhttp3.HttpUrl
+import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import timber.log.Timber
+import java.util.concurrent.TimeUnit
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Owns the SSDP listener lifecycle, fetches each discovered LOCATION's
+ * device description XML, and projects discovered MediaRenderers into a
+ * `StateFlow<List<UpnpRoute>>` that [OutputPickerController] merges with
+ * system routes.
+ *
+ * Passive listen runs from process start (via `init`). Active discovery
+ * (an M-SEARCH burst) is triggered by [upgradeDiscovery] when the
+ * picker sheet opens; SSDP has no symmetric "downgrade" — the passive
+ * NOTIFY listener stays on for the process lifetime, so
+ * [downgradeDiscovery] is a no-op preserved for API parity with the
+ * MediaRouter-side controller.
+ *
+ * Discovered devices are de-duplicated by UDN: a repeated NOTIFY for
+ * the same speaker replaces the prior entry rather than appending a
+ * duplicate row to the picker.
+ */
+@Singleton
+class UpnpDiscoveryController @Inject constructor(
+    @ApplicationContext context: Context,
+    @ApplicationScope private val appScope: CoroutineScope,
+    private val okHttp: OkHttpClient,
+) {
+    private val ssdp = SsdpDiscovery(context)
+
+    // Transport commands (play/pause/seek/next) and the 1 Hz poll go through
+    // this client. A dead renderer should fail fast so OutputPickerController's
+    // drop-recovery reverts to the phone in ~2 s instead of the shared client's
+    // 10 s connect timeout. Derived via newBuilder() so the connection pool +
+    // dispatcher stay shared with the app client.
+    private val controlHttp: OkHttpClient = okHttp.newBuilder()
+        .connectTimeout(CONTROL_CONNECT_TIMEOUT_SECONDS, TimeUnit.SECONDS)
+        .build()
+
+    private val routesInternal = MutableStateFlow<List<UpnpRoute>>(emptyList())
+    val routes: StateFlow<List<UpnpRoute>> = routesInternal.asStateFlow()
+
+    private val sonosTopologyInternal = MutableStateFlow<List<SonosZoneGroup>>(emptyList())
+    val sonosTopology: StateFlow<List<SonosZoneGroup>> = sonosTopologyInternal.asStateFlow()
+
+    init {
+        ssdp.start(appScope)
+        // appScope is process-lifetime (SupervisorJob + Dispatchers.Default),
+        // so the launched collector dies with the process — no explicit
+        // cancellation needed.
+        appScope.launch(Dispatchers.IO) {
+            ssdp.discoveries.collect { locationUrl -> handleDiscovery(locationUrl) }
+        }
+    }
+
+    /**
+     * Fire an M-SEARCH burst so newly-paired speakers appear within a
+     * few seconds rather than waiting for the next NOTIFY beacon
+     * (typical SSDP cadence: every ~30min — far too slow for a UI
+     * that just opened).
+     */
+    fun upgradeDiscovery() {
+        appScope.launch { ssdp.requestActiveScan() }
+    }
+
+    /**
+     * No-op for the SSDP socket — passive NOTIFY listen is always on
+     * once [init] has run. Kept symmetric with the MediaRouter side's
+     * `downgradeDiscovery` so the picker controller fans out to both
+     * without conditional logic.
+     */
+    fun downgradeDiscovery() {
+        // intentionally empty: see kdoc
+    }
+
+    /**
+     * Build an [AVTransportClient] bound to the previously-discovered
+     * route's control URL. Returns null when the routeId isn't in the
+     * current snapshot — the speaker disappeared between picker open
+     * and tap, or the caller passed a non-UPnP routeId. Callers handle
+     * the null by abandoning the selection (no crash, no fallback).
+     */
+    fun transportFor(routeId: String): AVTransportClient? {
+        val route = routesInternal.value.firstOrNull { it.id == routeId } ?: return null
+        return AVTransportClient(
+            loggingSoapClient(controlHttp, route.name),
+            route.avTransportControlUrl,
+        )
+    }
+
+    private suspend fun handleDiscovery(locationUrl: String) {
+        val route = fetchRoute(locationUrl) ?: return
+        upsertRoute(route)
+        if (route.manufacturer.contains("Sonos", ignoreCase = true)) {
+            refreshSonosTopology(route)
+        }
+    }
+
+    private fun upsertRoute(route: UpnpRoute) {
+        val current = routesInternal.value
+        val idx = current.indexOfFirst { it.id == route.id }
+        routesInternal.value = if (idx < 0) {
+            current + route
+        } else {
+            current.toMutableList().also { it[idx] = route }
+        }
+    }
+
+    private suspend fun refreshSonosTopology(anySonos: UpnpRoute) {
+        val zgtUrl = anySonos.zoneGroupTopologyControlUrl ?: run {
+            Timber.w(
+                "Sonos %s has no ZoneGroupTopology URL -- topology grouping disabled",
+                anySonos.id,
+            )
+            return
+        }
+        val groups = runCatching {
+            ZoneGroupTopologyClient(
+                loggingSoapClient(okHttp, "ZGT-${anySonos.id}"),
+                zgtUrl,
+            ).getZoneGroupState()
+        }
+            .onFailure { Timber.w(it, "refreshSonosTopology failed for %s", anySonos.id) }
+            .getOrNull() ?: return
+        Timber.w(
+            "Sonos topology refreshed for %s: %d group(s)",
+            anySonos.id,
+            groups.size,
+        )
+        sonosTopologyInternal.value = groups
+    }
+
+    /**
+     * Returns the coordinator UDN's full route for the group [udn] belongs
+     * to, or null if topology hasn't loaded / the udn is in no group. UDN
+     * normalization strips the "uuid:" prefix because DeviceDescription's
+     * <UDN> carries it but Sonos's ZoneGroupState Coordinator attr does not.
+     */
+    fun coordinatorRouteFor(udn: String): UpnpRoute? {
+        val bare = udn.bareUdn()
+        val coord = sonosTopologyInternal.value
+            .firstOrNull { g -> g.members.any { it.udn.bareUdn() == bare } }
+            ?.coordinatorUdn ?: return null
+        return routesInternal.value.firstOrNull { it.id.bareUdn() == coord.bareUdn() }
+    }
+
+    /**
+     * UDNs of every NON-coordinator Sonos group member. The picker
+     * controller suppresses these from the visible list.
+     */
+    fun nonCoordinatorMemberUdns(): Set<String> {
+        return sonosTopologyInternal.value.flatMap { g ->
+            g.members.map { it.udn.bareUdn() }
+                .filter { it != g.coordinatorUdn.bareUdn() }
+        }.toSet()
+    }
+
+    /**
+     * Fetch + parse the device description at [locationUrl] into a
+     * [UpnpRoute]. Returns null on URL parse failure, transport
+     * failure, empty body, or non-renderer device. Single-return form
+     * (chained `let`s + an early null guard) so detekt's default
+     * ReturnCount cap is respected.
+     */
+    private fun fetchRoute(locationUrl: String): UpnpRoute? {
+        val url = locationUrl.toHttpUrlOrNull() ?: return null
+        return fetchBody(url)
+            ?.let { DeviceDescription.parse(it, url) }
+            ?.let { desc ->
+                UpnpRoute(
+                    id = desc.udn,
+                    name = displayName(desc.friendlyName, desc.manufacturer),
+                    manufacturer = desc.manufacturer,
+                    modelName = desc.modelName,
+                    avTransportControlUrl = desc.avTransportControlUrl,
+                    renderingControlUrl = desc.renderingControlUrl,
+                    zoneGroupTopologyControlUrl = desc.zoneGroupTopologyControlUrl,
+                )
+            }
+    }
+
+    /**
+     * Clean the raw UPnP friendlyName for picker display. Sonos uses
+     * the format `Room - Device Type - RINCON_<UDN>`; we strip
+     * everything after the first " - " so the chip shows just "Living
+     * Room" / "Kitchen" / etc. Generic UPnP devices (Yamaha, Samsung
+     * TV, etc.) often append a "(192.168.x.x)" IP suffix; strip that
+     * too. Empty / blank → "Network speaker" fallback.
+     *
+     * Device subtitle (manufacturer + model) is rendered separately
+     * by the picker sheet, so room-only here doesn't lose information.
+     */
+    private fun displayName(friendlyName: String, manufacturer: String): String {
+        val trimmed = friendlyName.trim()
+        if (trimmed.isBlank()) return "Network speaker"
+        val byVendor = when {
+            manufacturer.contains("Sonos", ignoreCase = true) -> {
+                trimmed.substringBefore(" - ", trimmed)
+            }
+            else -> trimmed
+        }
+        val withoutIpSuffix = byVendor.replace(IP_SUFFIX_REGEX, "").trim()
+        return withoutIpSuffix.ifBlank { "Network speaker" }
+    }
+
+    private fun fetchBody(url: HttpUrl): String? {
+        val body = runCatching {
+            okHttp.newCall(Request.Builder().url(url).build()).execute().use {
+                it.body?.string()
+            }
+        }.getOrNull().orEmpty()
+        return body.ifEmpty { null }
+    }
+
+    private companion object {
+        // " (192.168.0.77)" trailing host suffix some generic UPnP
+        // devices append. Anchored to end-of-string so it never eats
+        // a legitimate parenthetical inside a name.
+        val IP_SUFFIX_REGEX = Regex("""\s*\(\d+\.\d+\.\d+\.\d+\)$""")
+
+        // Aggressive connect timeout for transport SOAP so a dead renderer
+        // trips the drop-recovery quickly. Conservative enough not to false-drop
+        // a slow-but-alive LAN; read timeout still inherits the shared client.
+        const val CONTROL_CONNECT_TIMEOUT_SECONDS = 2L
+    }
+}
+
+/**
+ * Normalize a Sonos UDN to its bare RINCON form for cross-comparison.
+ *
+ * Three places use UDN strings with different conventions:
+ *  - DeviceDescription's <UDN> tag carries the `uuid:` prefix.
+ *  - Sonos exposes one UDN per embedded device. The MediaRenderer adds
+ *    a `_MR` suffix and the MediaServer adds `_MS`.
+ *  - The ZGT GetZoneGroupState response uses bare `RINCON_xxx` with
+ *    neither the `uuid:` prefix nor any device suffix.
+ *
+ * To compare any pair of those, strip the prefix and the suffix so
+ * everything reduces to the underlying speaker identity.
+ */
+internal fun String.bareUdn(): String = removePrefix("uuid:")
+    .removeSuffix("_MR")
+    .removeSuffix("_MS")

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/UpnpRoute.kt

@@ -0,0 +1,28 @@
+package com.fabledsword.minstrel.player.output.upnp
+
+import okhttp3.HttpUrl
+
+/**
+ * A discovered UPnP / DLNA MediaRenderer (Sonos, Yamaha MusicCast,
+ * Bose SoundTouch, generic DLNA renderers). Lifted out of the SOAP /
+ * SSDP details so the picker UI consumes a narrow domain shape.
+ *
+ * Sonos devices additionally populate [zoneGroupTopologyControlUrl] from the
+ * ZoneGroupTopology service in their device description; non-Sonos devices
+ * leave it null. The discovery controller uses that URL to aggregate stereo
+ * pairs and multi-speaker groups into single picker rows.
+ *
+ * [id] is the device UDN (e.g. `uuid:RINCON_ABC...`). [name] is the
+ * raw `<friendlyName>` straight from the device description — callers
+ * fall back to "Network speaker" upstream when it's blank; this class
+ * does not perform that substitution itself.
+ */
+data class UpnpRoute(
+    val id: String,
+    val name: String,
+    val manufacturer: String,
+    val modelName: String,
+    val avTransportControlUrl: HttpUrl,
+    val renderingControlUrl: HttpUrl?,
+    val zoneGroupTopologyControlUrl: HttpUrl? = null,
+)

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/sonos/SonosTopology.kt

@@ -0,0 +1,90 @@
+package com.fabledsword.minstrel.player.output.upnp.sonos
+
+import org.xmlpull.v1.XmlPullParser
+import org.xmlpull.v1.XmlPullParserFactory
+
+/**
+ * One Sonos zone group as exposed by ZoneGroupTopology.GetZoneGroupState.
+ * Stereo pairs and multi-speaker groups all appear as one group with
+ * multiple members; one member is the coordinator we send SOAP to.
+ */
+data class SonosZoneGroup(
+    val coordinatorUdn: String,
+    val name: String,
+    val members: List<SonosZoneMember>,
+)
+
+data class SonosZoneMember(
+    val udn: String,
+    val roomName: String,
+    val location: String?,
+    val channelMapSet: String?,
+)
+
+object SonosTopology {
+
+    fun parse(xml: String): List<SonosZoneGroup> {
+        val effective = if (xml.contains("&lt;ZoneGroup")) {
+            unescapeXmlEntities(xml)
+        } else {
+            xml
+        }
+        return runCatching { parseStrict(effective) }.getOrDefault(emptyList())
+    }
+
+    private fun unescapeXmlEntities(s: String): String = s
+        .replace("&lt;", "<")
+        .replace("&gt;", ">")
+        .replace("&quot;", "\"")
+        .replace("&apos;", "'")
+        .replace("&amp;", "&")  // must be last to avoid double-decoding
+
+    private fun parseStrict(xml: String): List<SonosZoneGroup> {
+        val parser = XmlPullParserFactory.newInstance().newPullParser().apply {
+            setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true)
+            setInput(xml.reader())
+        }
+        val groups = mutableListOf<SonosZoneGroup>()
+        var currentCoordinator: String? = null
+        var currentMembers: MutableList<SonosZoneMember>? = null
+        while (parser.eventType != XmlPullParser.END_DOCUMENT) {
+            when (parser.eventType) {
+                XmlPullParser.START_TAG -> when (parser.name) {
+                    TAG_ZONE_GROUP -> {
+                        currentCoordinator = parser.getAttributeValue(null, ATTR_COORDINATOR)
+                        currentMembers = mutableListOf()
+                    }
+                    TAG_ZONE_GROUP_MEMBER -> currentMembers?.add(memberOf(parser))
+                }
+                XmlPullParser.END_TAG -> if (parser.name == TAG_ZONE_GROUP) {
+                    val members = currentMembers ?: emptyList()
+                    val coord = currentCoordinator
+                    if (coord != null && members.isNotEmpty()) {
+                        val name = members.firstOrNull { it.udn == coord }?.roomName
+                            ?: members.first().roomName
+                        groups.add(SonosZoneGroup(coord, name, members))
+                    }
+                    currentCoordinator = null
+                    currentMembers = null
+                }
+            }
+            parser.next()
+        }
+        return groups
+    }
+
+    private fun memberOf(parser: XmlPullParser): SonosZoneMember = SonosZoneMember(
+        udn = parser.getAttributeValue(null, ATTR_UUID).orEmpty(),
+        roomName = parser.getAttributeValue(null, ATTR_ZONE_NAME).orEmpty(),
+        location = parser.getAttributeValue(null, ATTR_LOCATION),
+        channelMapSet = parser.getAttributeValue(null, ATTR_CHANNEL_MAP_SET),
+    )
+
+    private const val TAG_ZONE_GROUP = "ZoneGroup"
+    private const val TAG_ZONE_GROUP_MEMBER = "ZoneGroupMember"
+    private const val ATTR_COORDINATOR = "Coordinator"
+    private const val ATTR_UUID = "UUID"
+    private const val ATTR_ZONE_NAME = "ZoneName"
+    private const val ATTR_LOCATION = "Location"
+    private const val ATTR_CHANNEL_MAP_SET = "ChannelMapSet"
+}

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/sonos/ZoneGroupTopologyClient.kt

@@ -0,0 +1,37 @@
+package com.fabledsword.minstrel.player.output.upnp.sonos
+
+import com.fabledsword.minstrel.player.output.upnp.SoapClient
+import okhttp3.HttpUrl
+import timber.log.Timber
+
+/**
+ * Sonos's proprietary ZoneGroupTopology service. Same SOAP shape as a
+ * standard UPnP service, exposed on port 1400 at
+ * /ZoneGroupTopology/Control. GetZoneGroupState returns the full
+ * network topology as one XML doc wrapped inside a SOAP arg.
+ */
+class ZoneGroupTopologyClient(
+    private val soap: SoapClient,
+    private val controlUrl: HttpUrl,
+) {
+    suspend fun getZoneGroupState(): List<SonosZoneGroup> {
+        val args = soap.call(
+            controlUrl = controlUrl,
+            serviceType = SERVICE_TYPE,
+            action = "GetZoneGroupState",
+            args = emptyMap(),
+        )
+        val inner = args["ZoneGroupState"].orEmpty()
+        Timber.w(
+            "ZGT extracted ZoneGroupState (%d chars): %s",
+            inner.length,
+            inner.take(ZGT_LOG_TRUNCATE_CHARS),
+        )
+        return SonosTopology.parse(inner)
+    }
+
+    private companion object {
+        const val SERVICE_TYPE = "urn:schemas-upnp-org:service:ZoneGroupTopology:1"
+        const val ZGT_LOG_TRUNCATE_CHARS = 2048
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/ui/DominantColor.kt

@@ -59,9 +59,14 @@ fun rememberDominantColor(coverUrl: String?): Color {
         val palette = withContext(Dispatchers.Default) {
             Palette.from(bitmap).generate()
         }
-        val swatch = palette.vibrantSwatch
-            ?: palette.mutedSwatch
-            ?: palette.dominantSwatch
+        // Always use the dominant (majority-by-pixel-count) swatch.
+        // The cover art is the main feature of this view; a vibrant
+        // accent on the cover should pop against the background, not
+        // be matched by it. Previously we tried vibrant first, which
+        // picked the highest-saturation swatch even when it covered
+        // a tiny fraction of the cover — small bright accents made
+        // the gradient feel disconnected from the actual image.
+        val swatch = palette.dominantSwatch
         if (swatch != null) {
             extracted = Color(swatch.rgb)
         }

android/app/src/main/java/com/fabledsword/minstrel/player/ui/MiniPlayer.kt

@@ -17,6 +17,7 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -164,6 +165,7 @@ fun MiniPlayer(
             MiniRow(
                 track = track,
                 isPlaying = state.isPlaying,
+                isUpnpLoading = state.isUpnpLoading,
                 isLiked = isLiked,
                 onExpandClick = onExpandClick,
                 onPlayPause = { if (state.isPlaying) viewModel.pause() else viewModel.play() },
@@ -204,6 +206,7 @@ private fun MiniProgressFill(positionMs: Long, durationMs: Long) {
 private fun MiniRow(
     track: TrackRef,
     isPlaying: Boolean,
+    isUpnpLoading: Boolean,
     isLiked: Boolean,
     onExpandClick: () -> Unit,
     onPlayPause: () -> Unit,
@@ -248,15 +251,39 @@ private fun MiniRow(
         }
         LikeButton(liked = isLiked, onToggle = onToggleLike)
         TransportButton(icon = Lucide.SkipBack, description = "Previous", onClick = onPrev)
-        TransportButton(
-            icon = if (isPlaying) Lucide.Pause else Lucide.Play,
-            description = if (isPlaying) "Pause" else "Play",
+        MiniPlayPauseButton(
+            isPlaying = isPlaying,
+            isUpnpLoading = isUpnpLoading,
             onClick = onPlayPause,
         )
         TransportButton(icon = Lucide.SkipForward, description = "Next", onClick = onNext)
     }
 }
 
+@Composable
+private fun MiniPlayPauseButton(
+    isPlaying: Boolean,
+    isUpnpLoading: Boolean,
+    onClick: () -> Unit,
+) {
+    IconButton(onClick = onClick, enabled = !isUpnpLoading) {
+        if (isUpnpLoading) {
+            CircularProgressIndicator(
+                modifier = Modifier.size(MINI_PLAY_PAUSE_SPINNER_DP.dp),
+                strokeWidth = 2.dp,
+            )
+        } else {
+            Icon(
+                imageVector = if (isPlaying) Lucide.Pause else Lucide.Play,
+                contentDescription = if (isPlaying) "Pause" else "Play",
+                tint = MaterialTheme.colorScheme.onSurface,
+            )
+        }
+    }
+}
+
+private const val MINI_PLAY_PAUSE_SPINNER_DP = 24
+
 @Composable
 private fun TransportButton(
     icon: androidx.compose.ui.graphics.vector.ImageVector,

android/app/src/main/java/com/fabledsword/minstrel/player/ui/NowPlayingScreen.kt

@@ -2,8 +2,13 @@
 
 package com.fabledsword.minstrel.player.ui
 
+import android.Manifest
+import android.content.pm.PackageManager
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.animation.ExperimentalSharedTransitionApi
 import androidx.compose.foundation.background
+import androidx.compose.foundation.focusable
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.foundation.layout.Arrangement
@@ -12,13 +17,16 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.aspectRatio
+import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -31,7 +39,6 @@ import androidx.compose.material3.Scaffold
 import androidx.compose.foundation.interaction.MutableInteractionSource
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Slider
-import androidx.compose.ui.unit.DpSize
 import androidx.compose.material3.TopAppBar
 import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.ui.graphics.Brush
@@ -43,13 +50,26 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
+import androidx.compose.ui.focus.FocusRequester
+import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.ui.input.key.Key
+import androidx.compose.ui.input.key.KeyEvent
+import androidx.compose.ui.input.key.KeyEventType
+import androidx.compose.ui.input.key.key
+import androidx.compose.ui.input.key.onKeyEvent
+import androidx.compose.ui.input.key.type
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import androidx.core.content.ContextCompat
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation.NavHostController
@@ -65,6 +85,13 @@ import com.composables.icons.lucide.Shuffle
 import com.composables.icons.lucide.SkipBack
 import com.composables.icons.lucide.SkipForward
 import com.fabledsword.minstrel.player.RepeatMode
+import com.fabledsword.minstrel.player.output.ActiveUpnp
+import com.fabledsword.minstrel.player.output.DeviceChip
+import com.fabledsword.minstrel.player.output.OutputPickerSheet
+import com.fabledsword.minstrel.player.output.OutputPickerViewModel
+import com.fabledsword.minstrel.player.output.OutputRoute
+import com.fabledsword.minstrel.player.output.RouteSnapshot
+import kotlinx.coroutines.launch
 import com.fabledsword.minstrel.nav.AlbumDetail
 import com.fabledsword.minstrel.nav.ArtistDetail
 import com.fabledsword.minstrel.nav.HERO_KEY_NOW_PLAYING_COVER
@@ -85,6 +112,10 @@ private const val COVER_MAX_WIDTH_DP = 320
 private const val TRANSPORT_ICON_DP = 36
 private const val PLAY_PAUSE_ICON_DP = 56
 private const val POP_GRACE_MS = 500L
+private val SCRUB_TRACK_HEIGHT_DP = 4.dp
+private val SCRUB_TRACK_CORNER_DP = 2.dp
+private val SCRUB_THUMB_WIDTH_DP = 4.dp
+private val SCRUB_THUMB_HEIGHT_DP = 18.dp
 
 // Vertical drag-down threshold (in pixels) past which the gesture
 // pops the player. Matches Flutter's 80px threshold in spirit;
@@ -111,27 +142,30 @@ fun NowPlayingScreen(
             snackbarHostState.showSnackbar(msg)
         }
     }
+    LaunchedEffect(Unit) {
+        viewModel.dropEvents.collect { snackbarHostState.showSnackbar("Disconnected from $it") }
+    }
     val track = state.currentTrack
     if (track == null) {
-        // Session torn down (queue finished + auto-stop, or user cleared
-        // the queue from elsewhere). Pop back to whichever shell screen
-        // launched NowPlaying rather than stranding the user on an
-        // EmptyState with no escape. A short delay swallows the
-        // momentary null during MediaController IPC bind on cold-mount.
-        LaunchedEffect(Unit) {
-            kotlinx.coroutines.delay(POP_GRACE_MS)
-            if (viewModel.uiState.value.currentTrack == null) {
-                navController.popBackStack()
-            }
-        }
+        NowPlayingNullTrackGuard(navController, viewModel)
         return
     }
+    val outputViewModel: OutputPickerViewModel = hiltViewModel()
+    val activeUpnp by outputViewModel.activeUpnp.collectAsStateWithLifecycle()
+    val onKeyEvent = rememberUpnpVolumeKeyHandler(activeUpnp)
+    val focusRequester = remember { FocusRequester() }
+    LaunchedEffect(activeUpnp) { if (activeUpnp != null) focusRequester.requestFocus() }
     val dominant = rememberDominantColor(track.coverUrl)
     val dismissConnection = rememberDragDismissConnection(
         onDismiss = { navController.popBackStack() },
     )
     Scaffold(
-        modifier = Modifier.fillMaxSize().nestedScroll(dismissConnection),
+        modifier = Modifier
+            .fillMaxSize()
+            .nestedScroll(dismissConnection)
+            .focusRequester(focusRequester)
+            .focusable()
+            .onKeyEvent(onKeyEvent),
         topBar = { NowPlayingTopBar(onClose = { navController.popBackStack() }) },
         snackbarHost = { SnackbarHost(snackbarHostState) },
         containerColor = Color.Transparent,
@@ -148,11 +182,32 @@ fun NowPlayingScreen(
                 navController = navController,
                 viewModel = viewModel,
                 trackActionsViewModel = trackActionsViewModel,
+                outputViewModel = outputViewModel,
             )
         }
     }
 }
 
+/**
+ * Null-track guard extracted from [NowPlayingScreen] to keep that
+ * function under detekt's LongMethod ceiling. Session torn down
+ * (queue finished + auto-stop, or user cleared the queue from
+ * elsewhere). Pops back after a short grace delay so a momentary
+ * null during MediaController IPC bind on cold-mount doesn't flash.
+ */
+@Composable
+private fun NowPlayingNullTrackGuard(
+    navController: NavHostController,
+    viewModel: PlayerViewModel,
+) {
+    LaunchedEffect(Unit) {
+        kotlinx.coroutines.delay(POP_GRACE_MS)
+        if (viewModel.uiState.value.currentTrack == null) {
+            navController.popBackStack()
+        }
+    }
+}
+
 @Composable
 private fun dominantGradient(top: Color): Brush {
     val base = MaterialTheme.colorScheme.background
@@ -189,16 +244,32 @@ private fun rememberDragDismissConnection(
     object : NestedScrollConnection {
         private var accumulated = 0f
 
+        // One-shot latch. popBackStack is async — between the first
+        // dismissal and the screen actually leaving the composition,
+        // the user's finger is still down and more onPostScroll
+        // frames arrive. Without this guard the accumulator rebuilds
+        // and onDismiss() fires a second time, popping the screen
+        // BENEATH NowPlaying. If that leaves the back stack empty
+        // the NavHost renders nothing → black screen on resume.
+        private var dismissed = false
+
         override fun onPostScroll(
             consumed: Offset,
             available: Offset,
             source: NestedScrollSource,
         ): Offset {
-            if (source != NestedScrollSource.UserInput) return Offset.Zero
-            return if (available.y > 0f) {
+            // After dismissal, eat all remaining drag so the
+            // scrollable doesn't paint over-scroll deltas during the
+            // pop transition. Source guard folded into the `else if`
+            // chain so the function stays under detekt's ReturnCount
+            // ceiling of 2.
+            if (dismissed) return available
+            return if (source != NestedScrollSource.UserInput) {
+                Offset.Zero
+            } else if (available.y > 0f) {
                 accumulated += available.y
                 if (accumulated >= thresholdPx) {
-                    accumulated = 0f
+                    dismissed = true
                     onDismiss()
                 }
                 Offset(0f, available.y)
@@ -209,6 +280,7 @@ private fun rememberDragDismissConnection(
         }
 
         override suspend fun onPreFling(available: Velocity): Velocity {
+            if (dismissed) return available
             accumulated = 0f
             return Velocity.Zero
         }
@@ -235,6 +307,7 @@ private fun NowPlayingTopBar(onClose: () -> Unit) {
     )
 }
 
+@Suppress("LongParameterList") // Compose screen wiring — layout args, not logic
 @Composable
 private fun NowPlayingBody(
     inner: androidx.compose.foundation.layout.PaddingValues,
@@ -243,9 +316,47 @@ private fun NowPlayingBody(
     navController: NavHostController,
     viewModel: PlayerViewModel,
     trackActionsViewModel: TrackActionsViewModel,
+    outputViewModel: OutputPickerViewModel,
 ) {
     val isLiked by trackActionsViewModel.isLikedFlow(track.id)
         .collectAsStateWithLifecycle(initialValue = false)
+    val routes by outputViewModel.routes.collectAsStateWithLifecycle()
+    val sheetVisible by outputViewModel.sheetVisible.collectAsStateWithLifecycle()
+    val permissionDenied = rememberBluetoothPermissionState(sheetVisible)
+    NowPlayingContent(
+        inner = inner,
+        state = state,
+        track = track,
+        navController = navController,
+        viewModel = viewModel,
+        trackActionsViewModel = trackActionsViewModel,
+        routes = routes,
+        isLiked = isLiked,
+        onChipTapped = outputViewModel::onChipTapped,
+    )
+    if (sheetVisible) {
+        OutputPickerSheet(
+            snapshot = routes,
+            permissionDenied = permissionDenied,
+            onRouteSelected = outputViewModel::onRouteSelected,
+            onDismiss = outputViewModel::onSheetDismissed,
+        )
+    }
+}
+
+@Composable
+@Suppress("LongParameterList") // mirrors NowPlayingBody — pure layout wiring
+private fun NowPlayingContent(
+    inner: androidx.compose.foundation.layout.PaddingValues,
+    state: com.fabledsword.minstrel.player.PlayerUiState,
+    track: com.fabledsword.minstrel.models.TrackRef,
+    navController: NavHostController,
+    viewModel: PlayerViewModel,
+    trackActionsViewModel: TrackActionsViewModel,
+    routes: RouteSnapshot,
+    isLiked: Boolean,
+    onChipTapped: () -> Unit,
+) {
     Column(
         modifier = Modifier
             .fillMaxSize()
@@ -273,27 +384,94 @@ private fun NowPlayingBody(
             onToggleShuffle = viewModel::toggleShuffle,
             onCycleRepeat = viewModel::cycleRepeat,
         )
+        // Spec visibility rule: hide the chip when the only route is the
+        // built-in speaker — no picker is useful with one option. Chip
+        // reappears the moment a Bluetooth pair or wired plug arrives.
+        if (shouldShowChip(routes)) {
+            Spacer(Modifier.height(8.dp))
+            DeviceChip(
+                route = routes.current,
+                onClick = onChipTapped,
+                modifier = Modifier.align(Alignment.CenterHorizontally),
+            )
+        }
         Spacer(Modifier.height(4.dp))
-        val smoothPositionMs by rememberSmoothPositionMs(
-            positionMs = state.positionMs,
-            durationMs = state.durationMs,
-            isPlaying = state.isPlaying,
-        )
-        ScrubberRow(
-            positionMs = smoothPositionMs,
-            durationMs = state.durationMs,
-            onSeek = viewModel::seekTo,
-        )
-        Spacer(Modifier.height(4.dp))
-        TransportRow(
-            isPlaying = state.isPlaying,
-            onPrev = viewModel::skipToPrevious,
-            onPlayPause = { if (state.isPlaying) viewModel.pause() else viewModel.play() },
-            onNext = viewModel::skipToNext,
-        )
+        PlaybackControlsBlock(state = state, viewModel = viewModel)
     }
 }
 
+/**
+ * Scrubber + transport pair, sharing the smoothed playback position.
+ * Extracted from [NowPlayingContent] to keep that body under detekt's
+ * LongMethod ceiling — the two rows belong together (the scrubber's
+ * smoothed position would otherwise need to be hoisted into the
+ * caller just to thread it into the row below).
+ */
+@Composable
+private fun PlaybackControlsBlock(
+    state: com.fabledsword.minstrel.player.PlayerUiState,
+    viewModel: PlayerViewModel,
+) {
+    val smoothPositionMs by rememberSmoothPositionMs(
+        positionMs = state.positionMs,
+        durationMs = state.durationMs,
+        isPlaying = state.isPlaying,
+    )
+    ScrubberRow(
+        positionMs = smoothPositionMs,
+        durationMs = state.durationMs,
+        onSeek = viewModel::seekTo,
+    )
+    Spacer(Modifier.height(4.dp))
+    TransportRow(
+        isPlaying = state.isPlaying,
+        isUpnpLoading = state.isUpnpLoading,
+        onPrev = viewModel::skipToPrevious,
+        onPlayPause = { if (state.isPlaying) viewModel.pause() else viewModel.play() },
+        onNext = viewModel::skipToNext,
+    )
+}
+
+/**
+ * One-shot BLUETOOTH_CONNECT permission flow tied to picker-sheet
+ * visibility. The launcher is remembered across recompositions; the
+ * LaunchedEffect fires when the sheet opens and the permission is not
+ * already granted. Subsequent opens are no-ops once the user has
+ * answered — the system remembers their choice. Returns whether the
+ * user explicitly denied, so the sheet can surface the rationale row.
+ *
+ * Extracted from [NowPlayingBody] to keep that body under detekt's
+ * LongMethod ceiling — the permission plumbing is incidental to the
+ * player layout.
+ */
+@Composable
+private fun rememberBluetoothPermissionState(sheetVisible: Boolean): Boolean {
+    val context = LocalContext.current
+    var permissionDenied by remember { mutableStateOf(false) }
+    val permissionLauncher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.RequestPermission(),
+    ) { granted ->
+        permissionDenied = !granted
+    }
+    LaunchedEffect(sheetVisible) {
+        if (sheetVisible &&
+            ContextCompat.checkSelfPermission(
+                context,
+                Manifest.permission.BLUETOOTH_CONNECT,
+            ) != PackageManager.PERMISSION_GRANTED
+        ) {
+            permissionLauncher.launch(Manifest.permission.BLUETOOTH_CONNECT)
+        }
+    }
+    return permissionDenied
+}
+
+private fun shouldShowChip(snapshot: RouteSnapshot): Boolean {
+    val onlyBuiltIn = snapshot.available.size == 1 &&
+        snapshot.available.first().kind == OutputRoute.Kind.BuiltIn
+    return !onlyBuiltIn
+}
+
 @Composable
 private fun BottomActionsRow(
     navController: NavHostController,
@@ -458,18 +636,28 @@ private fun ScrubberRow(positionMs: Long, durationMs: Long, onSeek: (Long) -> Un
         modifier = Modifier.fillMaxWidth(),
         colors = sliderColors,
         interactionSource = interactionSource,
-        // Slim 10dp thumb shrinks the scrubber's visual weight. M3
-        // default is 20dp; halving keeps it tappable (Slider's own
-        // 48dp hit slop is unchanged) but lets it recede into the UI.
-        // Track left at default — the colour pin alone already
-        // matches Flutter's slate look.
+        // Thin vertical pill (4dp wide × 18dp tall, fully rounded).
+        // A small circle on a thin horizontal bar reads as visually
+        // off-center even when geometrically aligned — the eye
+        // expects the bar to bisect the thumb but a 14dp circle's
+        // mass extends above and below in equal amounts that the
+        // brain perceives as offset. A vertical pill the same width
+        // as the track removes the ambiguity: the bar passes through
+        // the pill's horizontal axis cleanly. Also matches M3's
+        // expressive-slider handle direction. State-layer halo is
+        // still dropped for visual parity with the web scrubber.
+        // Slider's 48dp hit slop still applies, so tapability is
+        // unchanged.
         thumb = {
-            SliderDefaults.Thumb(
-                interactionSource = interactionSource,
-                colors = sliderColors,
-                thumbSize = DpSize(10.dp, 10.dp),
+            Box(
+                modifier = Modifier
+                    .size(width = SCRUB_THUMB_WIDTH_DP, height = SCRUB_THUMB_HEIGHT_DP)
+                    .clip(CircleShape)
+                    .background(accent),
             )
         },
+        // Custom 4dp rounded track — see ScrubTrack for rationale.
+        track = { _ -> ScrubTrack(fraction = fraction, accent = accent) },
     )
     Row(
         modifier = Modifier.fillMaxWidth(),
@@ -488,9 +676,37 @@ private fun ScrubberRow(positionMs: Long, durationMs: Long, onSeek: (Long) -> Un
     }
 }
 
+/**
+ * Custom 4dp rounded scrubber track. M3's default Track is 16dp tall
+ * and reads as a heavy pill rather than a measurement line; the
+ * pill-thumb-on-thin-track pairing restores the "handle on a string"
+ * cue your eye reads as "tool, draggable." Also drops M3's stop
+ * indicator dot, which the web scrubber doesn't have. Extracted so
+ * [ScrubberRow] stays under detekt's LongMethod ceiling.
+ */
+@Composable
+private fun ScrubTrack(fraction: Float, accent: Color) {
+    Box(modifier = Modifier.fillMaxWidth().height(SCRUB_TRACK_HEIGHT_DP)) {
+        Box(
+            modifier = Modifier
+                .matchParentSize()
+                .clip(RoundedCornerShape(SCRUB_TRACK_CORNER_DP))
+                .background(MaterialTheme.colorScheme.surfaceVariant),
+        )
+        Box(
+            modifier = Modifier
+                .fillMaxWidth(fraction)
+                .fillMaxHeight()
+                .clip(RoundedCornerShape(SCRUB_TRACK_CORNER_DP))
+                .background(accent),
+        )
+    }
+}
+
 @Composable
 private fun TransportRow(
     isPlaying: Boolean,
+    isUpnpLoading: Boolean,
     onPrev: () -> Unit,
     onPlayPause: () -> Unit,
     onNext: () -> Unit,
@@ -509,13 +725,20 @@ private fun TransportRow(
                 modifier = Modifier.size(TRANSPORT_ICON_DP.dp),
             )
         }
-        IconButton(onClick = onPlayPause) {
-            Icon(
-                imageVector = if (isPlaying) Lucide.Pause else Lucide.Play,
-                contentDescription = if (isPlaying) "Pause" else "Play",
-                tint = actionColors.primary,
-                modifier = Modifier.size(PLAY_PAUSE_ICON_DP.dp),
-            )
+        IconButton(onClick = onPlayPause, enabled = !isUpnpLoading) {
+            if (isUpnpLoading) {
+                CircularProgressIndicator(
+                    modifier = Modifier.size(PLAY_PAUSE_ICON_DP.dp),
+                    strokeWidth = 3.dp,
+                )
+            } else {
+                Icon(
+                    imageVector = if (isPlaying) Lucide.Pause else Lucide.Play,
+                    contentDescription = if (isPlaying) "Pause" else "Play",
+                    tint = actionColors.primary,
+                    modifier = Modifier.size(PLAY_PAUSE_ICON_DP.dp),
+                )
+            }
         }
         IconButton(onClick = onNext) {
             Icon(
@@ -527,3 +750,40 @@ private fun TransportRow(
         }
     }
 }
+
+/**
+ * Returns a key-event handler that intercepts volume-up/down when a UPnP
+ * route is active and routes the step through [ActiveUpnp.rendering].
+ * Volume is cached locally so rapid key presses don't each wait on a
+ * getVolume() round-trip. Returns false (not consumed) for every event
+ * when no UPnP route is active so the system handles volume normally.
+ */
+@Composable
+private fun rememberUpnpVolumeKeyHandler(activeUpnp: ActiveUpnp?): (KeyEvent) -> Boolean {
+    val scope = rememberCoroutineScope()
+    val cache = remember(activeUpnp?.routeId) { VolumeCache() }
+    return remember(activeUpnp) {
+        handler@{ event: KeyEvent ->
+            val rc = activeUpnp?.rendering ?: return@handler false
+            if (event.type != KeyEventType.KeyDown) return@handler false
+            val delta = when (event.key) {
+                Key.VolumeUp -> VOLUME_KEY_STEP
+                Key.VolumeDown -> -VOLUME_KEY_STEP
+                else -> return@handler false
+            }
+            scope.launch {
+                val current = cache.value ?: runCatching { rc.getVolume() }.getOrNull() ?: 0
+                val next = (current + delta).coerceIn(VOLUME_MIN_PERCENT, VOLUME_MAX_PERCENT)
+                cache.value = next
+                runCatching { rc.setVolume(next) }
+            }
+            true
+        }
+    }
+}
+
+private class VolumeCache(var value: Int? = null)
+
+private const val VOLUME_KEY_STEP = 5
+private const val VOLUME_MIN_PERCENT = 0
+private const val VOLUME_MAX_PERCENT = 100

android/app/src/main/java/com/fabledsword/minstrel/player/ui/PlayerViewModel.kt

@@ -4,6 +4,7 @@ import androidx.lifecycle.ViewModel
 import com.fabledsword.minstrel.player.PlayerController
 import com.fabledsword.minstrel.player.PlayerUiState
 import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.SharedFlow
 import kotlinx.coroutines.flow.StateFlow
 import javax.inject.Inject
 
@@ -24,6 +25,7 @@ class PlayerViewModel @Inject constructor(
 ) : ViewModel() {
 
     val uiState: StateFlow<PlayerUiState> = controller.uiState
+    val dropEvents: SharedFlow<String> = controller.dropEvents
 
     fun play() = controller.play()
     fun pause() = controller.pause()

android/app/src/main/java/com/fabledsword/minstrel/playlists/data/PlaylistPlayback.kt

@@ -0,0 +1,71 @@
+package com.fabledsword.minstrel.playlists.data
+
+import com.fabledsword.minstrel.models.PlaylistRef
+import com.fabledsword.minstrel.player.PlayerController
+import com.fabledsword.minstrel.api.ErrorCopy
+import kotlinx.coroutines.TimeoutCancellationException
+import kotlinx.coroutines.withTimeout
+
+private const val PLAYLIST_FETCH_TIMEOUT_MS = 8_000L
+
+/**
+ * Fetch a playlist and hand it to the player as a shuffled queue.
+ *
+ * Behavior matches the tile play-button contract used on Home and the
+ * Playlists list: refreshable system playlists go through systemShuffle
+ * (server-side rotation-aware order; tagging with the variant advances
+ * rotation), everything else uses refreshDetail. System playlists are
+ * then client-side shuffled so the tile feels random rather than
+ * "start at the rotation head". User playlists keep their authored
+ * order.
+ *
+ * Errors and empty mixes surface through [onMessage] for the caller to
+ * present as a snackbar / toast / etc. Returns when the player has
+ * accepted the queue (or an error path bailed).
+ */
+suspend fun playPlaylistShuffled(
+    playlist: PlaylistRef,
+    repository: PlaylistsRepository,
+    player: PlayerController,
+    onMessage: (String) -> Unit,
+) {
+    val detail = fetchPlaylistDetail(playlist, repository, onMessage) ?: return
+    val tracks = detail.tracks.toPlayableTrackRefs()
+    if (tracks.isEmpty()) {
+        onMessage("Mix isn't ready yet - try again in a moment")
+        return
+    }
+    // Drift #564: bare systemVariant string (not "playlist:<variant>") --
+    // server's rotation matcher keys on the bare variant.
+    val source = if (playlist.refreshable) playlist.systemVariant else null
+    // System playlist tile play button == "pick a random song + shuffle
+    // the rest" UX. Server's rotation-aware order still drives rotation
+    // bookkeeping via `source`; the client shuffle just removes the
+    // deterministic "start at rotation head" feel.
+    val ordered = if (playlist.isSystem) tracks.shuffled() else tracks
+    player.setQueue(ordered, initialIndex = 0, source = source)
+}
+
+private suspend fun fetchPlaylistDetail(
+    playlist: PlaylistRef,
+    repository: PlaylistsRepository,
+    onMessage: (String) -> Unit,
+): PlaylistDetailRef? = try {
+    withTimeout(PLAYLIST_FETCH_TIMEOUT_MS) {
+        if (playlist.refreshable && playlist.systemVariant != null) {
+            repository.systemShuffle(playlist.systemVariant)
+        } else {
+            repository.refreshDetail(playlist.id)
+        }
+    }
+} catch (
+    @Suppress("SwallowedException") _: TimeoutCancellationException,
+) {
+    onMessage("Couldn't load playlist - check your connection")
+    null
+} catch (
+    @Suppress("TooGenericExceptionCaught") e: Throwable,
+) {
+    onMessage("Couldn't load playlist: ${ErrorCopy.fromThrowable(e)}")
+    null
+}

android/app/src/main/java/com/fabledsword/minstrel/playlists/data/PlaylistsRepository.kt

@@ -7,6 +7,7 @@ import retrofit2.HttpException
 import java.net.HttpURLConnection
 import com.fabledsword.minstrel.cache.db.dao.CachedPlaylistDao
 import com.fabledsword.minstrel.cache.db.dao.CachedPlaylistTrackDao
+import com.fabledsword.minstrel.cache.db.dao.PlaylistCachedCount
 import com.fabledsword.minstrel.cache.db.entities.CachedPlaylistEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedPlaylistTrackEntity
 import com.fabledsword.minstrel.cache.mutations.MutationQueue
@@ -16,7 +17,9 @@ import com.fabledsword.minstrel.models.TrackRef
 import com.fabledsword.minstrel.models.wire.PlaylistDetailWire
 import com.fabledsword.minstrel.models.wire.PlaylistTrackWire
 import com.fabledsword.minstrel.models.wire.PlaylistWire
+import com.fabledsword.minstrel.shared.resolveServerUrl
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.map
 import retrofit2.Retrofit
 import retrofit2.create
@@ -50,9 +53,16 @@ class PlaylistsRepository @Inject constructor(
 
     // ── Reads (Flow, cache-first; the cache is the source of truth) ──
 
-    /** Owned + public; UI splits by isSystem / userId comparison. */
+    /**
+     * Owned + public; UI splits by isSystem / userId comparison. Joined with
+     * per-playlist cache counts so [PlaylistRef.fullyCached] drives the offline
+     * greying without each consumer re-querying the cache index.
+     */
     fun observeAll(): Flow<List<PlaylistRef>> =
-        playlistDao.observeAll().map { rows -> rows.map { it.toDomain() } }
+        combine(
+            playlistDao.observeAll(),
+            playlistDao.observeCachedCounts(),
+        ) { rows, counts -> mergePlaylistsWithCache(rows, counts) }
 
     /** User-owned playlists only (systemVariant IS NULL). */
     fun observeUserPlaylists(): Flow<List<PlaylistRef>> =
@@ -232,6 +242,23 @@ fun List<PlaylistTrackRef>.toPlayableTrackRefs(): List<TrackRef> =
 
 // ── Mappers (internal — keep Room + wire types out of the UI layer) ──
 
+/**
+ * Maps cached playlist rows to domain refs, stamping [PlaylistRef.fullyCached]
+ * from the cache-index counts. A playlist is fully cached when it has tracks
+ * and every member track is resident (`cachedCount >= trackCount`). Pulled out
+ * of the Flow so the predicate is unit-testable without a Room database.
+ */
+internal fun mergePlaylistsWithCache(
+    rows: List<CachedPlaylistEntity>,
+    counts: List<PlaylistCachedCount>,
+): List<PlaylistRef> {
+    val cachedById = counts.associate { it.playlistId to it.cachedCount }
+    return rows.map { row ->
+        val cached = cachedById[row.id] ?: 0
+        row.toDomain().copy(fullyCached = row.trackCount > 0 && cached >= row.trackCount)
+    }
+}
+
 private fun CachedPlaylistEntity.toDomain(): PlaylistRef =
     PlaylistRef(
         id = id,
@@ -241,7 +268,11 @@ private fun CachedPlaylistEntity.toDomain(): PlaylistRef =
         isPublic = isPublic,
         systemVariant = systemVariant,
         trackCount = trackCount,
-        coverUrl = coverPath ?: "",
+        // Server returns a relative cover path like "/api/playlists/<id>/cover";
+        // wrap through the placeholder host so BaseUrlInterceptor + the shared
+        // Coil/OkHttpClient resolve it against the live server. Without this
+        // wrap AsyncImage silently fails on the relative URL.
+        coverUrl = resolveServerUrl(coverPath) ?: "",
     )
 
 private fun PlaylistWire.toEntity(): CachedPlaylistEntity =
@@ -277,7 +308,10 @@ private fun PlaylistDetailWire.toPlaylistRef(): PlaylistRef =
         isPublic = isPublic,
         systemVariant = systemVariant,
         trackCount = trackCount,
-        coverUrl = coverUrl,
+        // Same relative-path wrap as CachedPlaylistEntity.toDomain — the wire
+        // gives us /api/playlists/<id>/cover and Coil needs the placeholder
+        // host for BaseUrlInterceptor to rewrite to the live server.
+        coverUrl = resolveServerUrl(coverUrl) ?: "",
         ownerUsername = ownerUsername,
     )
 

android/app/src/main/java/com/fabledsword/minstrel/playlists/ui/PlaylistDetailScreen.kt

@@ -87,7 +87,6 @@ import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.filter
-import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
@@ -141,8 +140,7 @@ class PlaylistDetailViewModel @Inject constructor(
     val regenerated: Flow<String> = regeneratedChannel.receiveAsFlow()
 
     val likedTrackIds: StateFlow<Set<String>> =
-        likes.observeLikedTracks()
-            .map { tracks -> tracks.mapTo(mutableSetOf()) { it.id } }
+        likes.observeLikedTrackIds()
             .stateIn(
                 scope = viewModelScope,
                 started = SharingStarted.WhileSubscribed(SHARE_STOP_TIMEOUT_MS),
@@ -227,7 +225,16 @@ class PlaylistDetailViewModel @Inject constructor(
         val refs = tracks.toPlayableTrackRefs()
         if (refs.isEmpty()) return
         val startIndex = refs.indexOfFirst { it.id == startTrackId }.coerceAtLeast(0)
-        player.setQueue(refs, initialIndex = startIndex, source = "playlist:$playlistId")
+        // Drift #564: for refreshable system playlists, send the bare
+        // systemVariant string so the rotation matcher
+        // (systemPlaylistSources in playevents/writer.go) sees the
+        // play. User playlists keep the "playlist:<id>" tag for
+        // attribution but it doesn't trigger rotation (intentional —
+        // rotation only applies to system mixes).
+        val playlist = (internal.value as? PlaylistDetailUiState.Success)?.detail?.playlist
+        val source = playlist?.systemVariant?.takeIf { playlist.refreshable }
+            ?: "playlist:$playlistId"
+        player.setQueue(refs, initialIndex = startIndex, source = source)
     }
 }
 
@@ -288,7 +295,10 @@ private fun PlaylistDetailContent(
     playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel,
     navController: NavHostController,
 ) {
-    Crossfade(targetState = state, label = "playlist-detail") { s -> when (s) {
+    // Crossfade keyed on `state::class` so refreshes that emit a
+    // fresh Success (same kind, new detail) don't re-fade the body;
+    // only Loading ↔ Success ↔ Error transitions animate.
+    Crossfade(targetState = state::class, label = "playlist-detail") { _ -> when (val s = state) {
         is PlaylistDetailUiState.Loading ->
             s.seed?.let { SeededPlaylistLoading(it) } ?: SkeletonPlaylistTrackList()
         is PlaylistDetailUiState.Error -> ErrorBlock(s.message, viewModel::refresh)

android/app/src/main/java/com/fabledsword/minstrel/playlists/ui/PlaylistsListScreen.kt

@@ -13,9 +13,13 @@ import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
@@ -23,11 +27,15 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewModelScope
 import androidx.navigation.NavHostController
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
+import com.fabledsword.minstrel.connectivity.ServerHealth
 import com.fabledsword.minstrel.events.EventsStream
 import com.fabledsword.minstrel.models.PlaylistRef
 import com.fabledsword.minstrel.nav.PlaylistDetail
 import com.fabledsword.minstrel.nav.Playlists
+import com.fabledsword.minstrel.player.PlayerController
 import com.fabledsword.minstrel.playlists.data.PlaylistsRepository
+import com.fabledsword.minstrel.playlists.data.playPlaylistShuffled
 import com.fabledsword.minstrel.shared.UiState
 import com.fabledsword.minstrel.shared.asCacheFirstStateFlow
 import com.fabledsword.minstrel.playlists.widgets.PlaylistCard
@@ -37,12 +45,19 @@ import com.fabledsword.minstrel.shared.widgets.MinstrelTopAppBar
 import com.fabledsword.minstrel.shared.widgets.PullToRefreshScaffold
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Job
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.receiveAsFlow
+import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
+private const val SHARE_STOP_TIMEOUT_MS = 5_000L
+
 // ─── State ───────────────────────────────────────────────────────────
 
 // ─── ViewModel ───────────────────────────────────────────────────────
@@ -50,9 +65,25 @@ import javax.inject.Inject
 @HiltViewModel
 class PlaylistsListViewModel @Inject constructor(
     private val repository: PlaylistsRepository,
+    private val player: PlayerController,
     private val eventsStream: EventsStream,
+    networkStatus: NetworkStatusController,
 ) : ViewModel() {
 
+    private val poolMessages = Channel<String>(Channel.BUFFERED)
+
+    /** Transient snackbar messages from playlist tile play taps. */
+    val transientMessages: Flow<String> = poolMessages.receiveAsFlow()
+
+    /** Cache-only: no link OR server unreachable (Unstable stays calm). Greys tiles. */
+    val offline: StateFlow<Boolean> = networkStatus.state
+        .map { it == ServerHealth.Offline || it == ServerHealth.ServerDown }
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(SHARE_STOP_TIMEOUT_MS),
+            initialValue = false,
+        )
+
     init {
         refresh()
         // Live updates: a playlist created/updated/deleted from another
@@ -69,6 +100,15 @@ class PlaylistsListViewModel @Inject constructor(
         runCatching { repository.refreshList() }
     }
 
+    /** Tile play button: shuffle the playlist's tracks and start at index 0. */
+    suspend fun playPlaylist(playlist: PlaylistRef) {
+        viewModelScope.launch {
+            playPlaylistShuffled(playlist, repository, player) {
+                poolMessages.trySend(it)
+            }
+        }.join()
+    }
+
     val uiState: StateFlow<UiState<List<PlaylistRef>>> =
         repository.observeAll()
             .map { list ->
@@ -88,6 +128,10 @@ fun PlaylistsListScreen(
     navController: NavHostController,
     viewModel: PlaylistsListViewModel = hiltViewModel(),
 ) {
+    val snackbar = remember { SnackbarHostState() }
+    LaunchedEffect(Unit) {
+        viewModel.transientMessages.collect { snackbar.showSnackbar(it) }
+    }
     Scaffold(
         modifier = Modifier.fillMaxSize(),
         topBar = {
@@ -97,8 +141,10 @@ fun PlaylistsListScreen(
                 currentRouteName = Playlists::class.qualifiedName,
             )
         },
+        snackbarHost = { SnackbarHost(snackbar) },
     ) { inner ->
         val state by viewModel.uiState.collectAsStateWithLifecycle()
+        val offline by viewModel.offline.collectAsStateWithLifecycle()
         PullToRefreshScaffold(
             onRefresh = { viewModel.refresh().join() },
             modifier = Modifier.fillMaxSize().padding(inner),
@@ -117,7 +163,9 @@ fun PlaylistsListScreen(
                 )
                 is UiState.Success -> PlaylistsGrid(
                     playlists = s.data,
+                    offline = offline,
                     onPlaylistClick = { id -> navController.navigate(PlaylistDetail(id)) },
+                    onPlay = viewModel::playPlaylist,
                 )
             }
         }
@@ -127,7 +175,9 @@ fun PlaylistsListScreen(
 @Composable
 private fun PlaylistsGrid(
     playlists: List<PlaylistRef>,
+    offline: Boolean,
     onPlaylistClick: (String) -> Unit,
+    onPlay: suspend (PlaylistRef) -> Unit,
 ) {
     val systemPlaylists = playlists.filter { it.isSystem }
     val userPlaylists = playlists.filter { !it.isSystem }
@@ -142,7 +192,16 @@ private fun PlaylistsGrid(
                 SectionHeader("System playlists")
             }
             items(items = systemPlaylists, key = { it.id }) { playlist ->
-                PlaylistCard(playlist = playlist, onClick = { onPlaylistClick(playlist.id) })
+                // Greyed offline when it needs the live server or isn't fully
+                // cached — dimmed but still tappable into the detail.
+                val greyed = offline && playlist.unavailableOffline
+                PlaylistCard(
+                    playlist = playlist,
+                    onClick = { onPlaylistClick(playlist.id) },
+                    onPlay = { onPlay(playlist) },
+                    playEnabled = playlist.trackCount > 0 && !greyed,
+                    greyed = greyed,
+                )
             }
         }
         if (userPlaylists.isNotEmpty()) {
@@ -150,7 +209,14 @@ private fun PlaylistsGrid(
                 SectionHeader("Your playlists")
             }
             items(items = userPlaylists, key = { it.id }) { playlist ->
-                PlaylistCard(playlist = playlist, onClick = { onPlaylistClick(playlist.id) })
+                val greyed = offline && playlist.unavailableOffline
+                PlaylistCard(
+                    playlist = playlist,
+                    onClick = { onPlaylistClick(playlist.id) },
+                    onPlay = { onPlay(playlist) },
+                    playEnabled = playlist.trackCount > 0 && !greyed,
+                    greyed = greyed,
+                )
             }
         }
     }

android/app/src/main/java/com/fabledsword/minstrel/playlists/widgets/PlaylistCard.kt

@@ -15,6 +15,7 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.alpha
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
@@ -40,6 +41,10 @@ import com.fabledsword.minstrel.theme.FabledSwordFlatTokens
  * [playEnabled] disables the overlay (50% alpha + ignore taps) — Home
  * uses it for system playlists in offline mode (their server-side
  * shuffle endpoint is unreachable) and for empty playlists.
+ *
+ * [greyed] dims the whole tile (it can't be reliably played offline) while
+ * keeping it tappable — the detail screen is the escape hatch for shuffling
+ * whatever subset is cached. Greyed always disables the play overlay too.
  */
 @Composable
 fun PlaylistCard(
@@ -48,11 +53,13 @@ fun PlaylistCard(
     modifier: Modifier = Modifier,
     onPlay: (suspend () -> Unit)? = null,
     playEnabled: Boolean = true,
+    greyed: Boolean = false,
 ) {
     val seedCache = LocalDetailSeedCache.current
     Surface(
         modifier = modifier
             .width(176.dp)
+            .alpha(if (greyed) GREYED_ALPHA else 1f) // dimmed, still clickable
             .clickable {
                 seedCache.stashPlaylist(playlist)
                 onClick()
@@ -63,7 +70,7 @@ fun PlaylistCard(
             PlaylistCardCover(
                 playlist = playlist,
                 onPlay = onPlay,
-                playEnabled = playEnabled,
+                playEnabled = playEnabled && !greyed,
             )
             Spacer(Modifier.height(8.dp))
             Text(
@@ -148,6 +155,7 @@ private fun VariantPill(label: String, modifier: Modifier = Modifier) {
 }
 
 private const val PILL_BG_ALPHA = 0.85f
+private const val GREYED_ALPHA = 0.45f
 
 private fun subtitleFor(playlist: PlaylistRef): String = when {
     playlist.trackCount > 0 -> "${playlist.trackCount} tracks"

android/app/src/main/java/com/fabledsword/minstrel/requests/ui/RequestsViewModel.kt

@@ -5,10 +5,13 @@ import androidx.lifecycle.viewModelScope
 import com.fabledsword.minstrel.api.ErrorCopy
 import com.fabledsword.minstrel.events.EventsStream
 import com.fabledsword.minstrel.models.RequestRef
+import com.fabledsword.minstrel.models.RequestStatus
+import com.fabledsword.minstrel.requests.data.CancelOutcome
 import com.fabledsword.minstrel.requests.data.RequestsRepository
 import com.fabledsword.minstrel.shared.UiState
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -19,6 +22,10 @@ import javax.inject.Inject
 
 private val RELEVANT_EVENT_KINDS = setOf("request.status_changed")
 
+// Cadence for in-flight request polling — matches the web client (#369):
+// fast enough to feel live, slow enough not to hammer the server.
+private const val POLL_INTERVAL_MS = 12_000L
+
 @HiltViewModel
 class RequestsViewModel @Inject constructor(
     private val repository: RequestsRepository,
@@ -30,11 +37,14 @@ class RequestsViewModel @Inject constructor(
 
     init {
         refresh()
+        // SSE push: reconciler completions arrive here; reload silently so the
+        // row updates in place rather than flashing the loading spinner.
         viewModelScope.launch {
             eventsStream.events
                 .filter { it.kind in RELEVANT_EVENT_KINDS }
-                .collect { refresh() }
+                .collect { silentReload() }
         }
+        viewModelScope.launch { pollWhileInFlight() }
     }
 
     fun refresh(): Job = viewModelScope.launch {
@@ -53,6 +63,43 @@ class RequestsViewModel @Inject constructor(
         }
     }
 
+    /**
+     * Auto-poll while any request is mid-ingest (status APPROVED), matching the
+     * web client (#369). Reloads silently every [POLL_INTERVAL_MS] and pauses
+     * when nothing is in-flight — complements the SSE push so progress stays
+     * live even if the event stream drops.
+     */
+    private suspend fun pollWhileInFlight() {
+        while (true) {
+            if (hasInFlightRequest()) {
+                silentReload()
+            }
+            delay(POLL_INTERVAL_MS)
+        }
+    }
+
+    private fun hasInFlightRequest(): Boolean {
+        val state = internal.value
+        return state is UiState.Success &&
+            state.data.any { it.status == RequestStatus.APPROVED }
+    }
+
+    /**
+     * Reload the list in place without flipping to Loading — used by the poll
+     * loop and the SSE collector so visible rows update without a spinner
+     * flash. A transient failure keeps the current view; the next reload wins.
+     */
+    private suspend fun silentReload() {
+        try {
+            val rows = repository.listMine()
+            internal.value = if (rows.isEmpty()) UiState.Empty else UiState.Success(rows)
+        } catch (
+            @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
+        ) {
+            // Keep the current view; the next poll / SSE / pull reconciles.
+        }
+    }
+
     /**
      * Optimistically removes [id] from the success list so the row
      * disappears immediately; on server-side success the row is
@@ -71,7 +118,7 @@ class RequestsViewModel @Inject constructor(
         }
         viewModelScope.launch {
             try {
-                val (_, updated) = repository.cancel(id)
+                val (outcome, updated) = repository.cancel(id)
                 if (updated != null) {
                     internal.update { state ->
                         if (state !is UiState.Success) {
@@ -87,12 +134,20 @@ class RequestsViewModel @Inject constructor(
                         }
                     }
                 }
-                // Refresh fetches the canonical list whether the cancel
-                // went through live (Synced) or got enqueued (Queued).
-                // The Queued case shows the optimistic removal until the
-                // replayer drains; the next list fetch surfaces the
-                // server's canonical view.
-                refresh()
+                // Drift #577: only refetch on the Synced outcome. The
+                // Queued path is offline by definition — the optimistic
+                // removal at the top of cancel() is correct, and a
+                // refresh() call here would either (a) get the
+                // not-yet-delivered cancelled row back from the server
+                // and snap it into the list (confusing), or (b) fail
+                // with a transport error and flip the whole screen to
+                // UiState.Error, making the user think the cancel
+                // failed. The mutation queue will replay the cancel
+                // when connectivity returns; the next on-screen refresh
+                // (pull-to-refresh, navigation back) reconciles.
+                if (outcome == CancelOutcome.Synced) {
+                    refresh()
+                }
             } catch (
                 @Suppress("TooGenericExceptionCaught", "SwallowedException") e: Throwable,
             ) {

android/app/src/main/java/com/fabledsword/minstrel/search/data/SearchRepository.kt

@@ -1,6 +1,11 @@
 package com.fabledsword.minstrel.search.data
 
 import com.fabledsword.minstrel.api.endpoints.SearchApi
+import com.fabledsword.minstrel.cache.db.dao.CachedAlbumDao
+import com.fabledsword.minstrel.cache.db.dao.CachedArtistDao
+import com.fabledsword.minstrel.cache.db.dao.CachedTrackDao
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
+import com.fabledsword.minstrel.connectivity.ServerHealth
 import com.fabledsword.minstrel.library.data.toDomain
 import com.fabledsword.minstrel.models.SearchResponseRef
 import retrofit2.Retrofit
@@ -8,17 +13,35 @@ import retrofit2.create
 import javax.inject.Inject
 import javax.inject.Singleton
 
+private const val LOCAL_SEARCH_LIMIT = 20
+
 /**
- * Thin Retrofit wrapper around `/api/search`. Debouncing lives in
- * the ViewModel, not here, so the repository stays trivial.
+ * Cache-first when offline. When [NetworkStatusController] reports Healthy or
+ * Unstable the repository hits `/api/search` and returns the server's three-facet
+ * paged response. When health is Offline or ServerDown it falls back to
+ * Room LIKE queries against `cached_*` so the user can still find
+ * something to play from what's already on the device; the outcome's
+ * [SearchOutcome.localOnly] flag lets the screen draw an "offline
+ * results" hint instead of pretending the server answered.
  */
 @Singleton
 class SearchRepository @Inject constructor(
     retrofit: Retrofit,
+    private val serverHealth: NetworkStatusController,
+    private val trackDao: CachedTrackDao,
+    private val albumDao: CachedAlbumDao,
+    private val artistDao: CachedArtistDao,
 ) {
     private val api: SearchApi = retrofit.create()
 
-    suspend fun search(query: String): SearchResponseRef {
+    suspend fun search(query: String): SearchOutcome = when (serverHealth.state.value) {
+        ServerHealth.Healthy, ServerHealth.Unstable ->
+            SearchOutcome(remoteSearch(query), localOnly = false)
+        ServerHealth.Offline, ServerHealth.ServerDown ->
+            SearchOutcome(localSearch(query), localOnly = true)
+    }
+
+    private suspend fun remoteSearch(query: String): SearchResponseRef {
         val wire = api.search(query)
         return SearchResponseRef(
             artists = wire.artists.items.map { it.toDomain() },
@@ -26,4 +49,21 @@ class SearchRepository @Inject constructor(
             tracks = wire.tracks.items.map { it.toDomain() },
         )
     }
+
+    private suspend fun localSearch(query: String): SearchResponseRef = SearchResponseRef(
+        artists = artistDao.searchByName(query, LOCAL_SEARCH_LIMIT).map { it.toDomain() },
+        albums = albumDao.searchByTitle(query, LOCAL_SEARCH_LIMIT).map { it.toDomain() },
+        tracks = trackDao.searchByTitle(query, LOCAL_SEARCH_LIMIT).map { it.toDomain() },
+    )
 }
+
+/**
+ * Wraps the search response with the signal of whether the result came
+ * from the server or from the local cached entities. The screen renders
+ * the same SearchResponseRef either way; the flag drives the offline
+ * banner copy.
+ */
+data class SearchOutcome(
+    val response: SearchResponseRef,
+    val localOnly: Boolean,
+)

android/app/src/main/java/com/fabledsword/minstrel/search/ui/SearchScreen.kt

@@ -158,17 +158,28 @@ private fun ResultsPane(
         is SearchResultsState.Error -> CenteredHint("Search failed: ${state.message}")
         is SearchResultsState.Loaded -> {
             if (state.response.isEmpty) {
-                CenteredHint("No matches for that query.")
-            } else {
-                ResultsList(
-                    response = state.response,
-                    playingTrackId = playingTrackId,
-                    onArtistClick = onArtistClick,
-                    onAlbumClick = onAlbumClick,
-                    onTrackPlay = onTrackPlay,
-                    onNavigateToAlbum = onNavigateToAlbum,
-                    onNavigateToArtist = onNavigateToArtist,
+                CenteredHint(
+                    if (state.localOnly) {
+                        "No matches in your on-device library."
+                    } else {
+                        "No matches for that query."
+                    },
                 )
+            } else {
+                Column(modifier = Modifier.fillMaxSize()) {
+                    if (state.localOnly) {
+                        OfflineResultsHint()
+                    }
+                    ResultsList(
+                        response = state.response,
+                        playingTrackId = playingTrackId,
+                        onArtistClick = onArtistClick,
+                        onAlbumClick = onAlbumClick,
+                        onTrackPlay = onTrackPlay,
+                        onNavigateToAlbum = onNavigateToAlbum,
+                        onNavigateToArtist = onNavigateToArtist,
+                    )
+                }
             }
         }
     }
@@ -308,6 +319,18 @@ private fun SectionHeader(label: String, count: Int) {
     }
 }
 
+@Composable
+private fun OfflineResultsHint() {
+    Text(
+        text = "Showing on-device matches only — the server is unreachable.",
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(horizontal = 16.dp, vertical = 6.dp),
+        style = MaterialTheme.typography.bodySmall,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+    )
+}
+
 @Composable
 private fun CenteredHint(text: String) {
     Box(modifier = Modifier.fillMaxSize().padding(24.dp), contentAlignment = Alignment.Center) {

android/app/src/main/java/com/fabledsword/minstrel/search/ui/SearchViewModel.kt

@@ -26,7 +26,10 @@ sealed interface SearchResultsState {
     /** Empty query — screen shows "type to search" hint. */
     data object Idle : SearchResultsState
     data object Loading : SearchResultsState
-    data class Loaded(val response: SearchResponseRef) : SearchResultsState
+    data class Loaded(
+        val response: SearchResponseRef,
+        val localOnly: Boolean = false,
+    ) : SearchResultsState
     data class Error(val message: String) : SearchResultsState
 }
 
@@ -98,8 +101,15 @@ class SearchViewModel @Inject constructor(
     private suspend fun runSearch(q: String) {
         internal.update { it.copy(results = SearchResultsState.Loading) }
         try {
-            val response = repository.search(q)
-            internal.update { it.copy(results = SearchResultsState.Loaded(response)) }
+            val outcome = repository.search(q)
+            internal.update {
+                it.copy(
+                    results = SearchResultsState.Loaded(
+                        response = outcome.response,
+                        localOnly = outcome.localOnly,
+                    ),
+                )
+            }
         } catch (
             @Suppress("TooGenericExceptionCaught") e: Throwable,
         ) {

android/app/src/main/java/com/fabledsword/minstrel/shared/widgets/PullRefreshNetworkViewModel.kt

@@ -0,0 +1,21 @@
+package com.fabledsword.minstrel.shared.widgets
+
+import androidx.lifecycle.SavedStateHandle
+import androidx.lifecycle.ViewModel
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
+import dagger.hilt.android.lifecycle.HiltViewModel
+import javax.inject.Inject
+
+/**
+ * Routes a deliberate pull-to-refresh into a /healthz recheck so the connection
+ * banner clears within seconds rather than waiting for the next poll — even on
+ * cache-only screens whose own refresh never touches the network. Backs
+ * [PullToRefreshScaffold].
+ */
+@HiltViewModel
+class PullRefreshNetworkViewModel @Inject constructor(
+    private val networkStatus: NetworkStatusController,
+    @Suppress("UnusedPrivateProperty") savedStateHandle: SavedStateHandle,
+) : ViewModel() {
+    fun recheck() = networkStatus.recheck()
+}

android/app/src/main/java/com/fabledsword/minstrel/shared/widgets/PullToRefreshScaffold.kt

@@ -10,12 +10,15 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import androidx.hilt.navigation.compose.hiltViewModel
 import kotlinx.coroutines.launch
 
 /**
  * Wraps [content] in a Material3 PullToRefreshBox so the user can
  * swipe-down to trigger [onRefresh]. The wrapper manages the
- * `isRefreshing` indicator while [onRefresh] is in flight.
+ * `isRefreshing` indicator while [onRefresh] is in flight. Every pull also
+ * fires a /healthz recheck (via [PullRefreshNetworkViewModel]) so a stale
+ * connection banner clears promptly on a deliberate user refresh.
  *
  * [onRefresh] is suspend: pass `{ viewModel.refresh().join() }` so the
  * indicator hides exactly when the underlying coroutine completes,
@@ -32,6 +35,7 @@ import kotlinx.coroutines.launch
 fun PullToRefreshScaffold(
     onRefresh: suspend () -> Unit,
     modifier: Modifier = Modifier,
+    netVm: PullRefreshNetworkViewModel = hiltViewModel(),
     content: @Composable () -> Unit,
 ) {
     var isRefreshing by remember { mutableStateOf(false) }
@@ -42,6 +46,7 @@ fun PullToRefreshScaffold(
             scope.launch {
                 isRefreshing = true
                 try {
+                    netVm.recheck() // deliberate pull → re-probe the server now
                     onRefresh()
                 } finally {
                     isRefreshing = false

android/app/src/main/java/com/fabledsword/minstrel/shared/widgets/ShellScaffold.kt

@@ -12,6 +12,7 @@ import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.hilt.navigation.compose.hiltViewModel
+import com.fabledsword.minstrel.cache.mutations.OfflineWriteHintViewModel
 import com.fabledsword.minstrel.connectivity.ui.ConnectionErrorBanner
 import com.fabledsword.minstrel.player.ui.MiniPlayer
 import com.fabledsword.minstrel.player.ui.PlaybackErrorViewModel
@@ -48,6 +49,7 @@ fun ShellScaffold(
     modifier: Modifier = Modifier,
     trackActionsViewModel: TrackActionsViewModel = hiltViewModel(),
     playbackErrorViewModel: PlaybackErrorViewModel = hiltViewModel(),
+    offlineWriteHintViewModel: OfflineWriteHintViewModel = hiltViewModel(),
     content: @Composable () -> Unit,
 ) {
     val snackbarHostState = remember { SnackbarHostState() }
@@ -61,6 +63,11 @@ fun ShellScaffold(
             snackbarHostState.showSnackbar(msg)
         }
     }
+    LaunchedEffect(Unit) {
+        offlineWriteHintViewModel.messages.collect { msg ->
+            snackbarHostState.showSnackbar(msg)
+        }
+    }
     // Consume the status-bar inset once here so the banner stack sits
     // below the status bar (mirrors Flutter's SafeArea(bottom:false)).
     // statusBarsPadding consumes the inset for descendants, so the in-

android/app/src/main/java/com/fabledsword/minstrel/shared/widgets/TrackRow.kt

@@ -1,5 +1,6 @@
 package com.fabledsword.minstrel.shared.widgets
 
+import android.widget.Toast
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
@@ -12,8 +13,14 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import com.fabledsword.minstrel.connectivity.LocalServerHealth
+import com.fabledsword.minstrel.connectivity.ServerHealth
+
+private const val OFFLINE_UNAVAILABLE_ALPHA = 0.4f
+private const val OFFLINE_TAP_MESSAGE = "Not downloaded — connect to play"
 
 /**
  * Shared track-list row. Replaces the 5 per-screen `TrackRow`s — every
@@ -30,6 +37,14 @@ import androidx.compose.ui.unit.dp
  * for applying its own alpha if it should match (the row doesn't
  * cascade because the trailing slot's content is the caller's, not
  * ours).
+ *
+ * Reads [LocalServerHealth] + [LocalCachedTrackIds] and intercepts taps
+ * on tracks that aren't downloaded when the server is unreachable —
+ * fires a Toast instead of attempting playback. The text dims so the
+ * user can see at a glance which rows in a long list will work offline.
+ * The trailing slot stays interactive so the kebab / like / playlist-
+ * add affordances can still queue mutations for offline replay (Phase
+ * 5 of #618 gates those at the action level).
  */
 @Composable
 fun TrackRow(
@@ -45,15 +60,31 @@ fun TrackRow(
     leading: @Composable () -> Unit = {},
     trailing: @Composable RowScope.() -> Unit = {},
 ) {
+    val context = LocalContext.current
+    val health = LocalServerHealth.current
+    // Unstable is non-gating — only a real gating state dims uncached rows.
+    val offlineUnavailable =
+        (health == ServerHealth.Offline || health == ServerHealth.ServerDown) &&
+            trackId !in LocalCachedTrackIds.current
     val titleColor = if (nowPlaying) {
         MaterialTheme.colorScheme.primary
     } else {
         MaterialTheme.colorScheme.onSurface
     }
+    val effectiveAlpha = if (offlineUnavailable) {
+        minOf(contentAlpha, OFFLINE_UNAVAILABLE_ALPHA)
+    } else {
+        contentAlpha
+    }
+    val effectiveOnClick: () -> Unit = if (offlineUnavailable) {
+        { Toast.makeText(context, OFFLINE_TAP_MESSAGE, Toast.LENGTH_SHORT).show() }
+    } else {
+        onClick
+    }
     Row(
         modifier = modifier
             .fillMaxWidth()
-            .clickable(enabled = enabled, onClick = onClick)
+            .clickable(enabled = enabled, onClick = effectiveOnClick)
             .padding(horizontal = 16.dp, vertical = 8.dp),
         verticalAlignment = Alignment.CenterVertically,
         horizontalArrangement = horizontalArrangement,
@@ -63,7 +94,7 @@ fun TrackRow(
             Text(
                 text = title,
                 style = MaterialTheme.typography.bodyLarge,
-                color = titleColor.copy(alpha = contentAlpha),
+                color = titleColor.copy(alpha = effectiveAlpha),
                 maxLines = 1,
                 overflow = TextOverflow.Ellipsis,
             )
@@ -71,7 +102,7 @@ fun TrackRow(
                 Text(
                     text = artist,
                     style = MaterialTheme.typography.bodySmall,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = contentAlpha),
+                    color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = effectiveAlpha),
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis,
                 )

android/app/src/main/java/com/fabledsword/minstrel/update/api/HealthzApi.kt

@@ -7,8 +7,8 @@ import retrofit2.http.GET
 /**
  * Retrofit interface for `GET /healthz` — unauthenticated health probe
  * returning the server's running version + the minimum client version
- * it'll talk to. Used by [com.fabledsword.minstrel.update.data.VersionCheckController]
- * to surface the VersionTooOld banner.
+ * it'll talk to. Polled by [com.fabledsword.minstrel.connectivity.NetworkStatusController]
+ * for both reachability and the VersionTooOld banner.
  */
 interface HealthzApi {
     @GET("healthz")

android/app/src/main/java/com/fabledsword/minstrel/update/data/VersionCheckController.kt

@@ -1,67 +0,0 @@
-package com.fabledsword.minstrel.update.data
-
-import com.fabledsword.minstrel.BuildConfig
-import com.fabledsword.minstrel.di.ApplicationScope
-import com.fabledsword.minstrel.update.api.HealthzApi
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.asStateFlow
-import kotlinx.coroutines.launch
-import retrofit2.Retrofit
-import javax.inject.Inject
-import javax.inject.Singleton
-
-private const val POLL_INTERVAL_MS = 5 * 60 * 1000L
-
-/**
- * Result of the most recent /healthz version-compatibility check.
- * `Skipped` means the server didn't include `min_client_version`
- * (partial deploy or older server) and the UI should not gate.
- */
-enum class VersionResult { OK, TOO_OLD, SKIPPED }
-
-/**
- * Polls /healthz periodically and exposes the current
- * [VersionResult] for the shell's VersionTooOld banner. Soft-fails
- * on network errors — keeps the last-known result rather than
- * showing a misleading "too old" on a connectivity blip.
- *
- * Constructed at app launch via the construct-the-singleton trick
- * in [com.fabledsword.minstrel.MinstrelApplication].
- */
-@Singleton
-class VersionCheckController @Inject constructor(
-    @ApplicationScope private val scope: CoroutineScope,
-    retrofit: Retrofit,
-) {
-    private val api: HealthzApi = retrofit.create(HealthzApi::class.java)
-
-    private val internal = MutableStateFlow(VersionResult.SKIPPED)
-    val result: StateFlow<VersionResult> = internal.asStateFlow()
-
-    init {
-        scope.launch {
-            while (true) {
-                runOnce()
-                delay(POLL_INTERVAL_MS)
-            }
-        }
-    }
-
-    /** One-shot recheck, bypassing the poll cadence. Used by the banner's "Check now" button. */
-    fun recheck() {
-        scope.launch { runOnce() }
-    }
-
-    private suspend fun runOnce() {
-        val response = runCatching { api.check() }.getOrNull() ?: return
-        val min = response.minClientVersion
-        internal.value = when {
-            min.isEmpty() -> VersionResult.SKIPPED
-            isVersionNewer(min, BuildConfig.VERSION_NAME) -> VersionResult.TOO_OLD
-            else -> VersionResult.OK
-        }
-    }
-}

android/app/src/main/java/com/fabledsword/minstrel/update/data/VersionResult.kt

@@ -0,0 +1,8 @@
+package com.fabledsword.minstrel.update.data
+
+/**
+ * Result of the most recent /healthz version-compatibility check.
+ * `SKIPPED` means the server didn't include `min_client_version`
+ * (partial deploy or older server) and the UI should not gate.
+ */
+enum class VersionResult { OK, TOO_OLD, SKIPPED }

android/app/src/main/java/com/fabledsword/minstrel/update/ui/VersionTooOldViewModel.kt

@@ -2,21 +2,21 @@ package com.fabledsword.minstrel.update.ui
 
 import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.ViewModel
-import com.fabledsword.minstrel.update.data.VersionCheckController
+import com.fabledsword.minstrel.connectivity.NetworkStatusController
 import com.fabledsword.minstrel.update.data.VersionResult
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.StateFlow
 import javax.inject.Inject
 
 /**
- * Tiny VM that exposes the [VersionCheckController]'s current
+ * Tiny VM that exposes the [NetworkStatusController]'s current
  * [VersionResult] plus its recheck trigger for the banner button.
  */
 @HiltViewModel
 class VersionTooOldViewModel @Inject constructor(
-    private val controller: VersionCheckController,
+    private val controller: NetworkStatusController,
     @Suppress("UnusedPrivateProperty") savedStateHandle: SavedStateHandle,
 ) : ViewModel() {
-    val result: StateFlow<VersionResult> = controller.result
+    val result: StateFlow<VersionResult> = controller.versionResult
     fun recheck() = controller.recheck()
 }

android/app/src/test/java/com/fabledsword/minstrel/api/AuthCookieInterceptorTest.kt

@@ -45,12 +45,26 @@ class AuthCookieInterceptorTest {
             }
         authStore = AuthStore(dao, TestScope(UnconfinedTestDispatcher()))
 
+        // BaseUrlInterceptor rewrites placeholder.invalid → mock server.
+        // AuthCookieInterceptor scopes its attach + clear behavior to
+        // the placeholder host so external Coil image fetches don't get
+        // the Minstrel session cookie attached and don't trigger a
+        // session-clear on 401. Tests issue requests to
+        // http://placeholder.invalid/... so the auth interceptor sees
+        // the in-scope host, and BaseUrlInterceptor (running AFTER, so
+        // the auth interceptor sees the original host) rewrites the URL
+        // before transport.
+        authStore.setBaseUrl(server.url("/").toString())
         client =
             OkHttpClient.Builder()
                 .addInterceptor(AuthCookieInterceptor(authStore))
+                .addInterceptor(BaseUrlInterceptor(authStore))
                 .build()
     }
 
+    private fun placeholderUrl(path: String): String =
+        "http://${BaseUrlInterceptor.PLACEHOLDER_HOST}$path"
+
     @AfterEach
     fun teardown() {
         server.shutdown()
@@ -61,7 +75,7 @@ class AuthCookieInterceptorTest {
         authStore.setSessionCookie("session=abc123")
         server.enqueue(MockResponse().setResponseCode(200))
 
-        client.newCall(Request.Builder().url(server.url("/api/test")).build()).execute()
+        client.newCall(Request.Builder().url(placeholderUrl("/api/test")).build()).execute()
 
         val recorded = server.takeRequest()
         assertEquals("session=abc123", recorded.getHeader("Cookie"))
@@ -72,7 +86,7 @@ class AuthCookieInterceptorTest {
         authStore.setSessionCookie("session=expired")
         server.enqueue(MockResponse().setResponseCode(401))
 
-        client.newCall(Request.Builder().url(server.url("/api/test")).build()).execute()
+        client.newCall(Request.Builder().url(placeholderUrl("/api/test")).build()).execute()
 
         assertNull(authStore.sessionCookie.value)
     }
@@ -85,7 +99,7 @@ class AuthCookieInterceptorTest {
                 .addHeader("Set-Cookie", "session=newvalue; Path=/; HttpOnly"),
         )
 
-        client.newCall(Request.Builder().url(server.url("/api/login")).build()).execute()
+        client.newCall(Request.Builder().url(placeholderUrl("/api/login")).build()).execute()
 
         assertEquals("session=newvalue", authStore.sessionCookie.value)
     }
@@ -95,8 +109,41 @@ class AuthCookieInterceptorTest {
         authStore.setSessionCookie("session=existing")
         server.enqueue(MockResponse().setResponseCode(200))
 
-        client.newCall(Request.Builder().url(server.url("/api/anything")).build()).execute()
+        client.newCall(Request.Builder().url(placeholderUrl("/api/anything")).build()).execute()
 
         assertEquals("session=existing", authStore.sessionCookie.value)
     }
+
+    // Drift #568 regression guard: requests to external hosts must NOT
+    // carry the Minstrel session cookie even when the auth store has
+    // one. The shared OkHttpClient is also used by Coil for image
+    // fetches to artwork.musicbrainz.org and the like; leaking the
+    // session cookie to those hosts is a posture violation.
+    @Test
+    fun `does NOT attach cookie to non-placeholder host`() {
+        authStore.setSessionCookie("session=secret")
+        server.enqueue(MockResponse().setResponseCode(200))
+
+        // Request goes directly to the mock server's host:port — NOT
+        // through the placeholder sentinel — so the auth interceptor
+        // should pass it through untouched.
+        client.newCall(Request.Builder().url(server.url("/external/image.jpg")).build()).execute()
+
+        val recorded = server.takeRequest()
+        assertNull(recorded.getHeader("Cookie"))
+    }
+
+    // Drift #569 regression guard: a 401 from an external host must
+    // NOT wipe the user's Minstrel session. A misbehaving CDN or a
+    // Lidarr that's 401-ing on /MediaCover URLs used to silently sign
+    // the user out.
+    @Test
+    fun `does NOT clear cookie on 401 from non-placeholder host`() {
+        authStore.setSessionCookie("session=keep")
+        server.enqueue(MockResponse().setResponseCode(401))
+
+        client.newCall(Request.Builder().url(server.url("/external/image.jpg")).build()).execute()
+
+        assertEquals("session=keep", authStore.sessionCookie.value)
+    }
 }

android/app/src/test/java/com/fabledsword/minstrel/api/BaseUrlInterceptorTest.kt

@@ -0,0 +1,130 @@
+package com.fabledsword.minstrel.api
+
+import com.fabledsword.minstrel.auth.AuthStore
+import com.fabledsword.minstrel.cache.db.dao.AuthSessionDao
+import io.mockk.coEvery
+import io.mockk.every
+import io.mockk.mockk
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import okhttp3.HttpUrl
+import okhttp3.OkHttpClient
+import okhttp3.Protocol
+import okhttp3.Request
+import okhttp3.Response
+import okhttp3.ResponseBody.Companion.toResponseBody
+import okhttp3.mockwebserver.MockResponse
+import okhttp3.mockwebserver.MockWebServer
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class BaseUrlInterceptorTest {
+    private lateinit var server: MockWebServer
+    private lateinit var authStore: AuthStore
+
+    @BeforeEach
+    fun setup() {
+        server = MockWebServer().apply { start() }
+        val dao =
+            mockk<AuthSessionDao> {
+                every { observe() } returns flowOf(null)
+                coEvery { get() } returns null
+                coEvery { upsert(any()) } returns Unit
+                coEvery { setSessionCookie(any()) } returns Unit
+                coEvery { setBaseUrl(any()) } returns Unit
+            }
+        authStore = AuthStore(dao, TestScope(UnconfinedTestDispatcher()))
+    }
+
+    @AfterEach
+    fun teardown() {
+        server.shutdown()
+    }
+
+    @Test
+    fun `rewrites placeholder host to live baseUrl host port and scheme`() {
+        // baseUrl points at the mock server; outbound request targets the
+        // placeholder sentinel — interceptor should rewrite to the mock.
+        authStore.setBaseUrl(server.url("/").toString())
+        server.enqueue(MockResponse().setResponseCode(200))
+        val client = OkHttpClient.Builder().addInterceptor(BaseUrlInterceptor(authStore)).build()
+
+        client.newCall(
+            Request.Builder().url("http://placeholder.invalid/api/test").build(),
+        ).execute()
+
+        val recorded = server.takeRequest()
+        assertEquals("/api/test", recorded.path)
+        // MockWebServer's recorded Host header is the rewritten host:port
+        assertEquals("${server.hostName}:${server.port}", recorded.getHeader("Host"))
+    }
+
+    @Test
+    fun `passes external absolute URL through unchanged`() {
+        // Lidarr-surfaced artwork hosts (artwork.musicbrainz.org,
+        // coverartarchive.org) are absolute external URLs. The
+        // interceptor must NOT rewrite them to the Minstrel base —
+        // doing so produces 404s the user saw as missing Discover
+        // suggestion covers.
+        authStore.setBaseUrl(server.url("/").toString())
+        var seen: HttpUrl? = null
+        val client =
+            OkHttpClient.Builder()
+                .addInterceptor(BaseUrlInterceptor(authStore))
+                .addInterceptor { chain ->
+                    seen = chain.request().url
+                    Response.Builder()
+                        .request(chain.request())
+                        .protocol(Protocol.HTTP_1_1)
+                        .code(200)
+                        .message("OK")
+                        .body("".toResponseBody())
+                        .build()
+                }
+                .build()
+
+        client.newCall(
+            Request.Builder()
+                .url("https://artwork.musicbrainz.org/release-group/abc/front-250.jpg")
+                .build(),
+        ).execute()
+
+        assertEquals("artwork.musicbrainz.org", seen?.host)
+        assertEquals("https", seen?.scheme)
+        assertEquals("/release-group/abc/front-250.jpg", seen?.encodedPath)
+    }
+
+    @Test
+    fun `falls through when stored baseUrl is unparseable`() {
+        // Empty / malformed baseUrl can happen between cold start and
+        // first AuthStore load; the interceptor should leave the
+        // request alone rather than throw.
+        authStore.setBaseUrl("not a url")
+        var seen: HttpUrl? = null
+        val client =
+            OkHttpClient.Builder()
+                .addInterceptor(BaseUrlInterceptor(authStore))
+                .addInterceptor { chain ->
+                    seen = chain.request().url
+                    Response.Builder()
+                        .request(chain.request())
+                        .protocol(Protocol.HTTP_1_1)
+                        .code(200)
+                        .message("OK")
+                        .body("".toResponseBody())
+                        .build()
+                }
+                .build()
+
+        client.newCall(
+            Request.Builder().url("http://placeholder.invalid/api/test").build(),
+        ).execute()
+
+        assertEquals("placeholder.invalid", seen?.host)
+    }
+}

android/app/src/test/java/com/fabledsword/minstrel/connectivity/ReachabilityMachineTest.kt

@@ -0,0 +1,116 @@
+package com.fabledsword.minstrel.connectivity
+
+import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class ReachabilityMachineTest {
+
+    private fun machine() = ReachabilityMachine()
+
+    @Test
+    fun `starts healthy`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        assertEquals(ServerHealth.Healthy, m.health())
+    }
+
+    @Test
+    fun `no link is offline regardless of probes`() {
+        val m = machine()
+        m.onLinkChange(up = false)
+        m.onProbeFailure(nowMs = 1)
+        assertEquals(ServerHealth.Offline, m.health())
+    }
+
+    @Test
+    fun `single probe failure is unstable not down`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        m.onProbeFailure(nowMs = 1_000)
+        assertEquals(ServerHealth.Unstable, m.health())
+    }
+
+    @Test
+    fun `probe success from unstable recovers to healthy`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        m.onProbeFailure(nowMs = 1_000)
+        m.onSuccess()
+        assertEquals(ServerHealth.Healthy, m.health())
+    }
+
+    @Test
+    fun `op success from unstable recovers to healthy`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        m.onProbeFailure(nowMs = 1_000)
+        m.onSuccess() // a successful stream read / API 2xx is self-proving
+        assertEquals(ServerHealth.Healthy, m.health())
+    }
+
+    @Test
+    fun `two op failures plus a failed probe escalate immediately`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        m.onOpFailure(nowMs = 1_000)
+        m.onOpFailure(nowMs = 1_500) // corroboration reached
+        m.onProbeFailure(nowMs = 2_000) // probe agrees → fast ServerDown
+        assertEquals(ServerHealth.ServerDown, m.health())
+    }
+
+    @Test
+    fun `op failures with a successful probe stay healthy (track-specific)`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        m.onOpFailure(nowMs = 1_000)
+        m.onOpFailure(nowMs = 1_500)
+        m.onSuccess() // arbiter says server is fine
+        assertEquals(ServerHealth.Healthy, m.health())
+    }
+
+    @Test
+    fun `stale op failures do not corroborate`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        m.onOpFailure(nowMs = 0)
+        m.onOpFailure(nowMs = 1_000)
+        // both op failures are now older than the corroboration window:
+        m.onProbeFailure(nowMs = 1_000 + CORROBORATION_WINDOW_MS + 1)
+        assertEquals(ServerHealth.Unstable, m.health()) // not enough fresh corroboration
+    }
+
+    @Test
+    fun `sustained failure backstop escalates after the window`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        m.onProbeFailure(nowMs = 1_000) // unstable, streak starts
+        m.onProbeFailure(nowMs = 1_000 + ESCALATE_AFTER_MS) // sustained ≥ backstop
+        assertEquals(ServerHealth.ServerDown, m.health())
+    }
+
+    @Test
+    fun `link restored keeps last-known down until a fresh result`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        m.onProbeFailure(nowMs = 1_000)
+        m.onProbeFailure(nowMs = 1_000 + ESCALATE_AFTER_MS) // ServerDown
+        m.onLinkChange(up = false)
+        assertEquals(ServerHealth.Offline, m.health())
+        m.onLinkChange(up = true)
+        // link back but no fresh probe result yet — last known reachability was down:
+        assertEquals(ServerHealth.ServerDown, m.health())
+        m.onSuccess()
+        assertEquals(ServerHealth.Healthy, m.health())
+    }
+
+    @Test
+    fun `unstable does not gate — it is not offline or serverdown`() {
+        val m = machine()
+        m.onLinkChange(up = true)
+        m.onProbeFailure(nowMs = 1_000)
+        val health = m.health()
+        assertTrue(health != ServerHealth.Offline && health != ServerHealth.ServerDown)
+        assertEquals(ServerHealth.Unstable, health)
+    }
+}

android/app/src/test/java/com/fabledsword/minstrel/home/ui/BuildPlaylistsRowTest.kt

@@ -0,0 +1,59 @@
+package com.fabledsword.minstrel.home.ui
+
+import com.fabledsword.minstrel.models.PlaylistRef
+import com.fabledsword.minstrel.models.SystemPlaylistsStatus
+import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class BuildPlaylistsRowTest {
+
+    private fun user(id: String, cached: Boolean) =
+        PlaylistRef(id = id, userId = "u", name = id, trackCount = 1, fullyCached = cached)
+
+    @Test
+    fun `offline row leads with pools then available before greyed`() {
+        val owned = listOf(user("partial", cached = false), user("full", cached = true))
+        val row = buildPlaylistsRow(owned, SystemPlaylistsStatus(), offline = true)
+
+        assertTrue(row[0] is PlaylistRowItem.OfflinePool)
+        assertTrue(row[1] is PlaylistRowItem.OfflinePool)
+        // Fully-cached "full" comes before the greyed "partial".
+        val reals = row.filterIsInstance<PlaylistRowItem.Real>().map { it.playlist.id }
+        assertEquals(listOf("full", "partial"), reals)
+    }
+
+    @Test
+    fun `offline greys a refreshable system playlist even when fully cached`() {
+        val forYou = PlaylistRef(
+            id = "fy",
+            userId = "u",
+            name = "For You",
+            systemVariant = "for_you",
+            trackCount = 1,
+            fullyCached = true,
+        )
+        val row = buildPlaylistsRow(
+            listOf(forYou, user("u1", cached = true)),
+            SystemPlaylistsStatus(),
+            offline = true,
+        )
+        // The fully-cached user playlist is available; the refreshable system
+        // mix needs the server, so it greys out and sorts after.
+        val reals = row.filterIsInstance<PlaylistRowItem.Real>().map { it.playlist.id }
+        assertEquals(listOf("u1", "fy"), reals)
+    }
+
+    @Test
+    fun `offline row drops building-pending placeholders`() {
+        val row = buildPlaylistsRow(emptyList(), SystemPlaylistsStatus(), offline = true)
+        assertTrue(row.none { it is PlaylistRowItem.Placeholder })
+    }
+
+    @Test
+    fun `online row has no offline pools and keeps system-slot placeholders`() {
+        val row = buildPlaylistsRow(emptyList(), SystemPlaylistsStatus(), offline = false)
+        assertTrue(row.none { it is PlaylistRowItem.OfflinePool })
+        assertTrue(row.any { it is PlaylistRowItem.Placeholder })
+    }
+}

android/app/src/test/java/com/fabledsword/minstrel/player/RemotePlayerStateTest.kt

@@ -0,0 +1,101 @@
+package com.fabledsword.minstrel.player
+
+import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class RemotePlayerStateTest {
+
+    @Test
+    fun `starts in idle state`() {
+        val state = RemotePlayerState()
+        assertFalse(state.isPlaying)
+        assertEquals(0L, state.positionMs)
+        assertEquals(0L, state.durationMs)
+    }
+
+    @Test
+    fun `applyPositionInfo updates position, duration, and trackNumber`() {
+        val state = RemotePlayerState()
+        state.applyPositionInfo(
+            positionMs = 65_000L, durationMs = 210_000L, trackUri = "x", trackNumber = 3,
+        )
+        assertEquals(65_000L, state.positionMs)
+        assertEquals(210_000L, state.durationMs)
+        assertEquals("x", state.currentTrackUri)
+        assertEquals(3, state.trackNumber)
+    }
+
+    @Test
+    fun `applyTransportPlaying flips isPlaying true`() {
+        val state = RemotePlayerState()
+        state.applyTransportPlaying()
+        assertTrue(state.isPlaying)
+    }
+
+    @Test
+    fun `applyTransportPaused flips isPlaying false`() {
+        val state = RemotePlayerState().apply { applyTransportPlaying() }
+        state.applyTransportPaused()
+        assertFalse(state.isPlaying)
+    }
+
+    @Test
+    fun `applyError resets to idle and records error`() {
+        val state = RemotePlayerState().apply { applyTransportPlaying() }
+        val ex = RuntimeException("disconnected")
+        state.applyError(ex)
+        assertFalse(state.isPlaying)
+        assertEquals(ex, state.lastError)
+    }
+
+    @Test
+    fun `recordPollFailure trips after threshold`() {
+        val state = RemotePlayerState()
+        // Threshold is 30 -- tolerate ~30s of screen-off WiFi sleep before
+        // declaring the remote dropped. Pre-threshold calls all return false.
+        repeat(DROP_THRESHOLD - 1) {
+            assertFalse(state.recordPollFailure())
+        }
+        assertTrue(state.recordPollFailure())
+    }
+
+    @Test
+    fun `recordPollSuccess clears the failure counter`() {
+        val state = RemotePlayerState()
+        repeat(DROP_THRESHOLD - 1) { state.recordPollFailure() }
+        state.recordPollSuccess()
+        assertFalse(state.recordPollFailure())
+    }
+
+    @Test
+    fun `play intent survives a SOAP error so a failed play can resume locally`() {
+        val state = RemotePlayerState()
+        state.setPlayIntent(true)
+        state.applyError(RuntimeException("connect timeout"))
+        // isPlaying is cleared by the error, but the operator's intent persists.
+        assertFalse(state.isPlaying)
+        assertTrue(state.lastPlayIntent)
+    }
+
+    @Test
+    fun `pausing clears play intent`() {
+        val state = RemotePlayerState()
+        state.setPlayIntent(true)
+        state.setPlayIntent(false)
+        assertFalse(state.lastPlayIntent)
+    }
+
+    @Test
+    fun `reset clears play intent`() {
+        val state = RemotePlayerState()
+        state.setPlayIntent(true)
+        state.reset()
+        assertFalse(state.lastPlayIntent)
+    }
+
+    private companion object {
+        const val DROP_THRESHOLD = 30
+    }
+}