fix(android): playlist like state + playlist cover URL

Two independent bugs surfaced together:

Bug 1: like button on tracks in playlist/album detail screens didn't
reflect actual liked state. LikesRepository.observeLikedTracks() does
a mapNotNull join against trackDao - a liked track whose row isn't in
the local cache yet (e.g. liked via web/notification, cache not
sync'd) gets DROPPED from the returned list. PlaylistDetailViewModel
+ AlbumDetailViewModel both used that as their like-set source, so
those rows showed as not-liked.

Adds LikesRepository.observeLikedTrackIds(): Flow<Set<String>> that
hits the DAO directly via observeLikedIdsOfType - no trackDao join,
no drops. The two ViewModels switch to it. LikedTab continues to use
observeLikedTracks because it needs the full TrackRef to render.

Bug 2: playlist cover art didn't render on the playlist detail
header. Server's derivePlaylistView returns CoverURL as the relative
path "/api/playlists/<id>/cover". PlaylistsRepository's two domain
mappers (CachedPlaylistEntity.toDomain + PlaylistDetailWire
.toPlaylistRef) stored it verbatim - Coil's AsyncImage can't fetch a
relative URL with no base, so the image silently failed.

Wraps the coverPath/coverUrl through resolveServerUrl so the
placeholder.invalid host triggers BaseUrlInterceptor's live-server
rewrite, same idiom every other cover surface (album / artist / track
/ playlist track rows) already uses.

System-playlist 24h refresh investigation pending - need to know how
you verified (server logs, DB state, or client-visible content)
before I can dig into the right layer.

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/likes/data/LikesRepository.kt

@@ -110,6 +110,20 @@ class LikesRepository @Inject constructor(
     fun observeIsLiked(entityType: String, entityId: String): Flow<Boolean> =
         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(currentUserId(), ENTITY_TRACK).first().toSet()

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

@@ -16,6 +16,7 @@ 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.map
 import retrofit2.Retrofit
@@ -241,7 +242,11 @@ 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 +282,10 @@ 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),