feat(flutter): show album name beneath artist in full player

Title (22pt parchment) → artist (14pt ash) → album (12pt ash). Album
is conditional — drops out if MediaItem.album is empty rather than
leaving a blank line. Tightened the gap to the seek bar (24→20) to
absorb the new line on small screens.

flutter_client/lib/player/now_playing_screen.dart

@@ -100,7 +100,16 @@ class _NowPlayingScreenState extends ConsumerState<NowPlayingScreen> {
                         maxLines: 1,
                         overflow: TextOverflow.ellipsis,
                       ),
-                      const SizedBox(height: 24),
+                      if ((media.album ?? '').isNotEmpty) ...[
+                        const SizedBox(height: 2),
+                        Text(
+                          media.album!,
+                          style: TextStyle(color: fs.ash, fontSize: 12),
+                          maxLines: 1,
+                          overflow: TextOverflow.ellipsis,
+                        ),
+                      ],
+                      const SizedBox(height: 20),
                       _SeekRow(position: pos, duration: dur, fs: fs, ref: ref),
                       const SizedBox(height: 8),
                       _PrimaryControls(