Checkpoint web-player design-system refactor and backend track genre tagging

Advances the ongoing token/componentization cleanup (anchored player dock,
border-based panels instead of floating shadows, corrected light-mode
accent/gradient tokens) alongside in-progress backend support for track
genre tags.

backend/Core/Musify.Application/Albums/GetAlbumTracks.cs

@@ -29,6 +29,7 @@ namespace Musify.Application.Albums
             var tracksQuery = database.AlbumHasTracks
                 .AsNoTracking()
                 .Include(albumTrack => albumTrack.Track.Owner)
+                .Include(albumTrack => albumTrack.Track.Tags)
                 .Where(albumTrack => albumTrack.AlbumId == request.AlbumId);
 
             var totalCount = await tracksQuery.CountAsync(cancellationToken);