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>

apps/web/src/widgets/Ambient.tsx

@@ -0,0 +1,17 @@
+import type { CSSProperties } from 'react';
+
+import s from './Ambient.module.css';
+
+/**
+ * Ambient-фон (docs/design.md#1): три размытых дрейфующих пятна; третье — в цвете обложки текущего трека.
+ * Отключается в настройках; при prefers-reduced-motion пятна неподвижны.
+ */
+export function Ambient({ color }: { color: string }) {
+  return (
+    <div className={s.ambient} aria-hidden>
+      <span className={s.a} />
+      <span className={s.b} />
+      <span className={s.c} style={{ '--amb-c3': `${color}99` } as CSSProperties} />
+    </div>
+  );
+}