feat(android): port cached_home_index (M8 4.2 slice 9)

Mirrors flutter_client/lib/cache/db.dart's CachedHomeIndex — per-item
rows that drive the Home screen sections (Recently Added Albums,
Rediscover Albums/Artists, Most Played Tracks, Last Played Artists).

Composite PK (section, position) — exactly one row per slot per
section; sync replaces in-place via upsert. entityType ("album" /
"artist" / "track") dispatches per-tile hydration to the right
per-entity endpoint when the Home screen renders.

DAO surface fits the sync flow:
  - observeBySection (Flow) for the Home composables
  - getBySection (suspend) for one-shot sync reads
  - upsertAll for sync writes
  - deleteBySection for replace-all on a section sync

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

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

@@ -6,6 +6,7 @@ import androidx.room.TypeConverters
 import com.fabledsword.minstrel.cache.db.dao.AudioCacheIndexDao
 import com.fabledsword.minstrel.cache.db.dao.CachedAlbumDao
 import com.fabledsword.minstrel.cache.db.dao.CachedArtistDao
+import com.fabledsword.minstrel.cache.db.dao.CachedHomeIndexDao
 import com.fabledsword.minstrel.cache.db.dao.CachedLikeDao
 import com.fabledsword.minstrel.cache.db.dao.CachedMutationDao
 import com.fabledsword.minstrel.cache.db.dao.CachedPlaylistDao
@@ -17,6 +18,7 @@ import com.fabledsword.minstrel.cache.db.dao.SyncMetadataDao
 import com.fabledsword.minstrel.cache.db.entities.AudioCacheIndexEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedAlbumEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedArtistEntity
+import com.fabledsword.minstrel.cache.db.entities.CachedHomeIndexEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedLikeEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedMutationEntity
 import com.fabledsword.minstrel.cache.db.entities.CachedPlaylistEntity
@@ -52,6 +54,7 @@ import com.fabledsword.minstrel.cache.db.entities.SyncMetadataEntity
         AudioCacheIndexEntity::class,
         CachedMutationEntity::class,
         CachedResumeStateEntity::class,
+        CachedHomeIndexEntity::class,
     ],
     version = 1,
     exportSchema = true,
@@ -69,4 +72,5 @@ abstract class AppDatabase : RoomDatabase() {
     abstract fun audioCacheIndexDao(): AudioCacheIndexDao
     abstract fun cachedMutationDao(): CachedMutationDao
     abstract fun cachedResumeStateDao(): CachedResumeStateDao
+    abstract fun cachedHomeIndexDao(): CachedHomeIndexDao
 }

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

@@ -0,0 +1,33 @@
+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.CachedHomeIndexEntity
+import kotlinx.coroutines.flow.Flow
+
+@Dao
+interface CachedHomeIndexDao {
+    @Query(
+        "SELECT * FROM cached_home_index " +
+            "WHERE section = :section ORDER BY position ASC",
+    )
+    fun observeBySection(section: String): Flow<List<CachedHomeIndexEntity>>
+
+    @Query(
+        "SELECT * FROM cached_home_index " +
+            "WHERE section = :section ORDER BY position ASC",
+    )
+    suspend fun getBySection(section: String): List<CachedHomeIndexEntity>
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    suspend fun upsertAll(rows: List<CachedHomeIndexEntity>)
+
+    /** Replace-all pattern; sync wipes a section then re-inserts. */
+    @Query("DELETE FROM cached_home_index WHERE section = :section")
+    suspend fun deleteBySection(section: String)
+
+    @Query("DELETE FROM cached_home_index")
+    suspend fun clear()
+}

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

@@ -0,0 +1,34 @@
+package com.fabledsword.minstrel.cache.db.entities
+
+import androidx.room.Entity
+import kotlinx.datetime.Clock
+import kotlinx.datetime.Instant
+
+/**
+ * Per-item row driving the Home screen sections. Mirrors
+ * `flutter_client/lib/cache/db.dart`'s `CachedHomeIndex` Drift table.
+ *
+ * `section` is one of (matching /api/home keys):
+ *   - "recently_added_albums"
+ *   - "rediscover_albums"
+ *   - "rediscover_artists"
+ *   - "most_played_tracks"
+ *   - "last_played_artists"
+ *
+ * `entityType` is "album" | "artist" | "track" — dispatches hydration
+ * to the right per-entity endpoint when a tile is rendered.
+ *
+ * The composite PK (section, position) means there's exactly one row
+ * per slot per section; sync replaces in-place by upsert.
+ */
+@Entity(
+    tableName = "cached_home_index",
+    primaryKeys = ["section", "position"],
+)
+data class CachedHomeIndexEntity(
+    val section: String,
+    val position: Int,
+    val entityType: String,
+    val entityId: String,
+    val fetchedAt: Instant = Clock.System.now(),
+)