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>

web-player/src/lib/player/liked.svelte.ts

@@ -6,6 +6,7 @@ export interface LikedTrack {
 	artist?: string;
 	explicit?: boolean;
 	ownerUserId?: string | number | null;
+	listensCount?: number | string;
 	likedAt: number;
 }
 
@@ -37,6 +38,7 @@ class LikedStore {
 				artist: item.artist,
 				explicit: item.explicit,
 				ownerUserId: item.ownerUserId,
+				listensCount: item.listensCount,
 				likedAt: new Date(tracks[i].createdAt).getTime()
 			};
 		});