feat(web): My Wave button, mood picker and endless wave playback (M4)

- WaveButton: TypeScript port of the prototype's canvas animation
  (orb and liquid), breathing at rest, pulsing to the track's BPM and
  energy in the cover palette, following the cursor, pressing with a
  spring; reduced motion and hidden tabs slow or stop it
- home: the wave in the centre with activity and mood chips; changing
  them while playing rebuilds the upcoming tracks without stopping
- player wave mode: asks for the next batch when two tracks are left,
  sends complete / skip / early skip / like / dislike as feedback and
  refreshes the queue right after a reaction or an early skip
- tracks expose bpm, energy and loudness once analysed; library page
  shows analysis progress and 7-day wave metrics; wave style setting

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/test/fakeApi.ts

@@ -17,6 +17,8 @@ const problem = (status: number, code: string, extra: object = {}) => json({ sta
 
 let seq = 0;
 
+const WAVE_ID = '00000000-0000-4000-8000-0000000000ee';
+
 const kino = { id: '00000000-0000-4000-8000-0000000000aa', name: 'Кино' };
 const albumRef = { id: '00000000-0000-4000-8000-0000000000bb', title: 'Группа крови', year: 1988, cover_url: null, cover_colors: [] };
 export const albumTracks = ['Группа крови', 'Закрой за мной дверь'].map((title, i) => ({
@@ -31,6 +33,7 @@ export const albumTracks = ['Группа крови', 'Закрой за мно
   available: true,
   stream_url: `/api/v1/stream/00000000-0000-4000-8000-00000000010${i}?sig=x`,
   reaction: null as 'like' | 'dislike' | null,
+  features: { bpm: 120, energy: 0.6, loudness_lufs: -12 },
 }));
 const albumSummary = {
   id: '00000000-0000-4000-8000-0000000000bb',
@@ -193,6 +196,21 @@ export function fakeApi(initial: FakeUser[]) {
           duration_ms: 400000,
           tracks: albumTracks.map((t) => ({ ...t, reaction: reactions.get(t.id) ?? null })),
         });
+      case 'GET /api/v1/wave/options':
+        return json({
+          activities: [{ key: 'running', icon: 'directions_run' }, { key: 'focus', icon: 'headphones' }],
+          moods: [{ key: 'calm', icon: 'spa' }, { key: 'happy', icon: 'sentiment_satisfied' }],
+        });
+      case 'POST /api/v1/wave/sessions':
+        return json(
+          { session_id: WAVE_ID, activity: body?.activity ?? null, mood: body?.mood ?? null, tracks: albumTracks, fallback: false },
+          201,
+        );
+      case `PATCH /api/v1/wave/sessions/${WAVE_ID}`:
+      case `POST /api/v1/wave/sessions/${WAVE_ID}/next`:
+        return json({ session_id: WAVE_ID, activity: body?.activity ?? null, mood: body?.mood ?? null, tracks: [], fallback: false });
+      case `DELETE /api/v1/wave/sessions/${WAVE_ID}`:
+        return new Response(null, { status: 204 });
       case 'POST /api/v1/events':
         return json({ accepted: (body?.events as unknown[]).length, duplicates: 0, rejected: 0 });
       case 'GET /api/v1/me/playback-state':