feat(web): align the web UI with the design prototype

- Ambient background in the app shell: three drifting blurred blobs,
  the third one tinted with the current track's cover; can be turned off
  in settings and stays still with reduced motion.
- Island player variant (floating glass panel) next to the bar, chosen
  in settings; player source line ("Album · …", "My Wave"), reactions
  around the transport controls, queue drawer.
- Sidebar: like / dislike counters, pending uploads badge on Queue,
  admin Settings page holding the upload queue limits.
- Collection: header tile with kicker, underline tabs, time / number
  lead column with an equalizer for the current track, album column,
  dimmed dislikes with undo, Play all / Shuffle pills.
- Album: cover-tinted header and Play / Shuffle; artist: artist wave,
  Play and popular tracks (new GET /artists/{id}/top-tracks).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

services/api/internal/library/catalog.go

@@ -132,6 +132,15 @@ func (st *Store) TracksByIDs(ctx context.Context, ids []uuid.UUID) ([]TrackRow,
 	return out, nil
 }
 
+// ArtistTopTracks — треки исполнителя (основной или приглашённый), самые слушаемые всеми пользователями первыми.
+func (st *Store) ArtistTopTracks(ctx context.Context, artistID uuid.UUID, limit int) ([]TrackRow, error) {
+	return st.queryTracks(ctx, `
+		WHERE t.id IN (SELECT track_id FROM track_artists WHERE artist_id = $1)
+		ORDER BY COALESCE((SELECT sum(s.play_count) FROM user_track_stats s WHERE s.track_id = t.id), 0) DESC,
+			t.created_at DESC
+		LIMIT $2`, artistID, limit)
+}
+
 // AlbumTracks — треки альбома по дискам и номерам.
 func (st *Store) AlbumTracks(ctx context.Context, albumID uuid.UUID) ([]TrackRow, error) {
 	return st.queryTracks(ctx, "WHERE t.album_id = $1 ORDER BY t.disc_no NULLS FIRST, t.track_no NULLS LAST, t.title", albumID)