feat(android): port cached_quarantine_mine (M8 4.2 slice 4)

Mirrors flutter_client/lib/cache/db.dart's CachedQuarantineMine —
the user's flagged-as-hidden tracks. Server returns the full
denormalized snapshot on /api/me/quarantine; the cache mirrors that
shape so the Quarantine screen renders without a join.

`createdAt` is a server ISO-8601 string (canonical timestamp);
`fetchedAt` is our local sync marker.

DAO covers the three known consumers:
  - observeAll for the Quarantine screen (newest first)
  - observeFlaggedTrackIds for feed-level filtering
  - observeIsHidden(trackId) scalar Flow for per-tile UI

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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

@@ -8,6 +8,7 @@ import com.fabledsword.minstrel.cache.db.dao.CachedArtistDao
 import com.fabledsword.minstrel.cache.db.dao.CachedLikeDao
 import com.fabledsword.minstrel.cache.db.dao.CachedPlaylistDao
 import com.fabledsword.minstrel.cache.db.dao.CachedPlaylistTrackDao
+import com.fabledsword.minstrel.cache.db.dao.CachedQuarantineDao
 import com.fabledsword.minstrel.cache.db.dao.CachedTrackDao
 import com.fabledsword.minstrel.cache.db.dao.SyncMetadataDao
 import com.fabledsword.minstrel.cache.db.entities.CachedAlbumEntity
@@ -15,6 +16,7 @@ import com.fabledsword.minstrel.cache.db.entities.CachedArtistEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedLikeEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedPlaylistEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedPlaylistTrackEntity
+import com.fabledsword.minstrel.cache.db.entities.CachedQuarantineEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedTrackEntity
 import com.fabledsword.minstrel.cache.db.entities.SyncMetadataEntity
 
@@ -40,6 +42,7 @@ import com.fabledsword.minstrel.cache.db.entities.SyncMetadataEntity
         CachedLikeEntity::class,
         CachedPlaylistEntity::class,
         CachedPlaylistTrackEntity::class,
+        CachedQuarantineEntity::class,
     ],
     version = 1,
     exportSchema = true,
@@ -53,4 +56,5 @@ abstract class AppDatabase : RoomDatabase() {
     abstract fun cachedLikeDao(): CachedLikeDao
     abstract fun cachedPlaylistDao(): CachedPlaylistDao
     abstract fun cachedPlaylistTrackDao(): CachedPlaylistTrackDao
+    abstract fun cachedQuarantineDao(): CachedQuarantineDao
 }

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

@@ -0,0 +1,36 @@
+package com.fabledsword.minstrel.cache.db.dao
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+import com.fabledsword.minstrel.cache.db.entities.CachedQuarantineEntity
+import kotlinx.coroutines.flow.Flow
+
+@Dao
+interface CachedQuarantineDao {
+    /** Newest-first listing for the Quarantine screen. */
+    @Query("SELECT * FROM cached_quarantine_mine ORDER BY createdAt DESC")
+    fun observeAll(): Flow<List<CachedQuarantineEntity>>
+
+    /** Just the IDs — feed-filtering code reads this to hide tracks. */
+    @Query("SELECT trackId FROM cached_quarantine_mine")
+    fun observeFlaggedTrackIds(): Flow<List<String>>
+
+    @Query(
+        "SELECT EXISTS(SELECT 1 FROM cached_quarantine_mine WHERE trackId = :trackId)",
+    )
+    fun observeIsHidden(trackId: String): Flow<Boolean>
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    suspend fun upsert(row: CachedQuarantineEntity)
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    suspend fun upsertAll(rows: List<CachedQuarantineEntity>)
+
+    @Query("DELETE FROM cached_quarantine_mine WHERE trackId = :trackId")
+    suspend fun deleteByTrackId(trackId: String)
+
+    @Query("DELETE FROM cached_quarantine_mine WHERE trackId IN (:trackIds)")
+    suspend fun deleteByTrackIds(trackIds: List<String>)
+}

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

@@ -0,0 +1,36 @@
+package com.fabledsword.minstrel.cache.db.entities
+
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+import kotlinx.datetime.Clock
+import kotlinx.datetime.Instant
+
+/**
+ * The current user's quarantine flag for one track. Mirrors
+ * `flutter_client/lib/cache/db.dart`'s `CachedQuarantineMine` Drift
+ * table.
+ *
+ * The flat denormalized track/album/artist columns let the Quarantine
+ * screen render off this single table without a join — the server
+ * returns the full snapshot on /api/me/quarantine so we mirror that
+ * shape locally.
+ *
+ * `createdAt` is the server-issued timestamp preserved as an opaque
+ * ISO-8601 string (it's the canonical "when this was flagged" value);
+ * `fetchedAt` is our local sync-time marker.
+ */
+@Entity(tableName = "cached_quarantine_mine")
+data class CachedQuarantineEntity(
+    @PrimaryKey val trackId: String,
+    val reason: String,
+    val notes: String? = null,
+    val createdAt: String,
+    val trackTitle: String,
+    val trackDurationMs: Int = 0,
+    val albumId: String,
+    val albumTitle: String,
+    val albumCoverArtPath: String? = null,
+    val artistId: String,
+    val artistName: String,
+    val fetchedAt: Instant = Clock.System.now(),
+)