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.

web-player/src/lib/api/schema.d.ts

@@ -743,6 +743,8 @@ export interface components {
             artist: null | string;
             /** Format: double */
             durationSeconds: number | string;
+            /** Format: int32 */
+            listensCount: number | string;
         };
         PaginatedResponseOfAlbumApplicationResponse: {
             items: components["schemas"]["AlbumApplicationResponse"][];