fix lint and session access from the notification star review

- opt in to the Media3 unstable API on the service and answer
  unsupported custom commands with SessionError.ERROR_NOT_SUPPORTED
- add the star command on top of the trust-aware connection defaults
  instead of granting untrusted controllers the full command set
- number tracks within their disc, not across the whole album
- leave the star button to the library flow so a failed write cannot
  leave the notification flipped
- omit the leading cell entirely when a row has no art and no track

app/src/main/kotlin/com/subtracks/playback/PlaybackService.kt

@@ -22,6 +22,7 @@ import androidx.media3.session.CommandButton
 import androidx.media3.session.MediaSession
 import androidx.media3.session.MediaSessionService
 import androidx.media3.session.SessionCommand
+import androidx.media3.session.SessionError
 import androidx.media3.session.SessionResult
 import coil3.SingletonImageLoader
 import com.google.common.util.concurrent.Futures
@@ -39,6 +40,7 @@ import kotlinx.coroutines.launch
 import okhttp3.OkHttpClient
 import org.koin.core.context.GlobalContext
 
+@OptIn(UnstableApi::class)
 class PlaybackService : MediaSessionService() {
     private var session: MediaSession? = null
     private var artworkLoader: CoverArtBitmapLoader? = null
@@ -55,15 +57,17 @@ class PlaybackService : MediaSessionService() {
             override fun onConnect(
                 session: MediaSession,
                 controller: MediaSession.ControllerInfo,
-            ): MediaSession.ConnectionResult =
-                MediaSession.ConnectionResult
-                    .AcceptedResultBuilder(session)
+            ): MediaSession.ConnectionResult {
+                val base = MediaSession.ConnectionResult.AcceptedResultBuilder(session, controller).build()
+                return MediaSession.ConnectionResult
+                    .AcceptedResultBuilder(session, controller)
                     .setAvailableSessionCommands(
-                        MediaSession.ConnectionResult.DEFAULT_SESSION_COMMANDS
+                        base.availableSessionCommands
                             .buildUpon()
                             .add(STAR_COMMAND)
                             .build(),
                     ).build()
+            }
 
             override fun onCustomCommand(
                 session: MediaSession,
@@ -72,7 +76,7 @@ class PlaybackService : MediaSessionService() {
                 args: Bundle,
             ): ListenableFuture<SessionResult> {
                 if (customCommand.customAction != STAR_COMMAND.customAction) {
-                    return Futures.immediateFuture(SessionResult(SessionResult.RESULT_ERROR_NOT_SUPPORTED))
+                    return Futures.immediateFuture(SessionResult(SessionError.ERROR_NOT_SUPPORTED))
                 }
                 toggleStar()
                 return Futures.immediateFuture(SessionResult(SessionResult.RESULT_SUCCESS))
@@ -163,8 +167,7 @@ class PlaybackService : MediaSessionService() {
     private fun toggleStar() {
         val songId = currentSongId ?: return
         val library = library ?: return
-        starred = !starred
-        library.star(StarType.Song, songId, starred)
+        library.star(StarType.Song, songId, !starred)
     }
 
     private fun starButton(isStarred: Boolean): CommandButton =
@@ -190,7 +193,6 @@ class PlaybackService : MediaSessionService() {
             }.build()
 
     override fun onDestroy() {
-        starJob?.cancel()
         scope.cancel()
         artworkLoader?.shutdown()
         artworkLoader = null

app/src/main/kotlin/com/subtracks/ui/library/AlbumDetailScreen.kt

@@ -132,6 +132,16 @@ fun AlbumDetailScreen(
                     }
             }
         }
+    val discOrdinals =
+        remember(songs) {
+            val counters = mutableMapOf<Long, Long>()
+            songs.associate { song ->
+                val disc = song.disc ?: 1L
+                val ordinal = (counters[disc] ?: 0L) + 1
+                counters[disc] = ordinal
+                song.id to ordinal
+            }
+        }
     HeroDetailScaffold(
         artwork = artwork,
         title = album?.name.orEmpty(),
@@ -171,7 +181,7 @@ fun AlbumDetailScreen(
                     SongRow(
                         song = song,
                         isPlaying = song.id == playingSongId,
-                        trackNumber = song.track ?: (index + 1).toLong(),
+                        trackNumber = song.track ?: discOrdinals[song.id],
                         durationSeconds = song.duration,
                         download = downloads[song.id],
                         modifier =

app/src/main/kotlin/com/subtracks/ui/library/SongsContent.kt

@@ -57,16 +57,24 @@ fun SongRow(
     ListItem(
         modifier = modifier,
         leadingContent =
-            if (coverArt != null) {
-                {
-                    CoverArtCell(
-                        ref = coverArt(coverArtId, true),
-                        name = song.album ?: song.title,
-                        isPlaying = isPlaying,
-                    )
+            when {
+                coverArt != null -> {
+                    {
+                        CoverArtCell(
+                            ref = coverArt(coverArtId, true),
+                            name = song.album ?: song.title,
+                            isPlaying = isPlaying,
+                        )
+                    }
+                }
+
+                trackNumber != null || isPlaying -> {
+                    { TrackCell(trackNumber, isPlaying) }
+                }
+
+                else -> {
+                    null
                 }
-            } else {
-                { TrackCell(trackNumber, isPlaying) }
             },
         trailingContent = {
             Row(