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>

api/openapi.yaml

@@ -894,6 +894,30 @@ paths:
                 $ref: "#/components/schemas/AlbumSummaryList"
         default:
           $ref: "#/components/responses/Problem"
+  /api/v1/artists/{id}/top-tracks:
+    parameters:
+      - $ref: "#/components/parameters/EntityId"
+    get:
+      operationId: listArtistTopTracks
+      tags: [catalog]
+      summary: Популярные треки исполнителя (по прослушиваниям всех пользователей)
+      parameters:
+        - name: limit
+          in: query
+          schema:
+            type: integer
+            minimum: 1
+            maximum: 50
+            default: 10
+      responses:
+        "200":
+          description: Треки, самые слушаемые первыми
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/TrackList"
+        default:
+          $ref: "#/components/responses/Problem"
   /api/v1/albums/{id}:
     parameters:
       - $ref: "#/components/parameters/EntityId"