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.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/Core/Musify.Application/Likes/GetLikedTracks.cs

@@ -23,6 +23,7 @@ namespace Musify.Application.Likes
             var likesQuery = database.TrackLikes
                 .AsNoTracking()
                 .Include(like => like.Track.Owner)
+                .Include(like => like.Track.Tags)
                 .Where(like => like.UserId == request.UserId);
 
             var totalCount = await likesQuery.CountAsync(cancellationToken);