fix(queue): resolve local album tracks by album_key

Load queue local album tracks from album_key when available and fall back
to album/artist matching with empty album_artist handling. Thread album_key
through grouped local album rows for more reliable navigation.

lib/screens/queue_tab.dart

@@ -2456,10 +2456,20 @@ class _QueueTabState extends ConsumerState<QueueTab> {
   Future<void> _navigateToLocalAlbum(_GroupedLocalAlbum album) async {
     var tracks = album.tracks;
     if (tracks.isEmpty && album.displayTrackCount > 0) {
-      final rows = await LibraryDatabase.instance.getQueueLocalAlbumTracks(
-        album.albumName,
-        album.artistName,
-      );
+      var rows = album.albumKey.isNotEmpty
+          ? await LibraryDatabase.instance.getQueueLocalAlbumTracksByKey(
+              album.albumKey,
+            )
+          : await LibraryDatabase.instance.getQueueLocalAlbumTracks(
+              album.albumName,
+              album.artistName,
+            );
+      if (rows.isEmpty && album.albumKey.isNotEmpty) {
+        rows = await LibraryDatabase.instance.getQueueLocalAlbumTracks(
+          album.albumName,
+          album.artistName,
+        );
+      }
       tracks = rows.map(LocalLibraryItem.fromJson).toList(growable: false);
       if (!mounted) return;
     }

lib/screens/queue_tab_helpers.dart

@@ -209,6 +209,7 @@ class _GroupedAlbum {
 }
 
 class _GroupedLocalAlbum {
+  final String albumKey;
   final String albumName;
   final String artistName;
   final String? coverPath;
@@ -218,6 +219,7 @@ class _GroupedLocalAlbum {
   final String searchKey;
 
   _GroupedLocalAlbum({
+    required this.albumKey,
     required this.albumName,
     required this.artistName,
     this.coverPath,
@@ -226,7 +228,7 @@ class _GroupedLocalAlbum {
     required this.latestScanned,
   }) : searchKey = '${albumName.toLowerCase()}|${artistName.toLowerCase()}';
 
-  String get key => '$albumName|$artistName';
+  String get key => albumKey;
 
   int get displayTrackCount => trackCount ?? tracks.length;
 }
@@ -480,6 +482,7 @@ final _queueLibraryPageProvider =
           if (source == 'local') {
             groupedLocalAlbums.add(
               _GroupedLocalAlbum(
+                albumKey: row['album_key'] as String? ?? '',
                 albumName: row['album_name'] as String? ?? '',
                 artistName: row['artist_name'] as String? ?? '',
                 coverPath: row['cover_path'] as String?,

lib/services/library_database.dart

@@ -967,7 +967,7 @@ class LibraryDatabase {
     final rows = await db.query(
       'library',
       where:
-          'LOWER(album_name) = ? AND LOWER(COALESCE(album_artist, artist_name)) = ?',
+          "LOWER(album_name) = ? AND LOWER(COALESCE(NULLIF(album_artist, ''), artist_name)) = ?",
       whereArgs: [albumName.toLowerCase(), artistName.toLowerCase()],
       orderBy:
           'COALESCE(disc_number, 0), COALESCE(track_number, 0), track_name',
@@ -975,6 +975,20 @@ class LibraryDatabase {
     return rows.map(_dbRowToJson).toList(growable: false);
   }
 
+  Future<List<Map<String, dynamic>>> getQueueLocalAlbumTracksByKey(
+    String albumKey,
+  ) async {
+    final db = await database;
+    final rows = await db.query(
+      'library',
+      where: 'album_key = ?',
+      whereArgs: [albumKey],
+      orderBy:
+          'COALESCE(disc_number, 0), COALESCE(track_number, 0), track_name',
+    );
+    return rows.map(_dbRowToJson).toList(growable: false);
+  }
+
   String _queueTrackUnionSql(QueueLibraryDbQuery request, List<Object?> args) {
     final parts = <String>[];
     if (request.source != 'local') {