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>

services/api/internal/library/catalog.go

@@ -38,6 +38,11 @@ type TrackRow struct {
 	Album      AlbumRow
 	Genres     []string
 	Available  bool
+	// Признаки анализа; Analyzed = false — трек ещё не проанализирован.
+	Analyzed     bool
+	BPM          *float32
+	Energy       *float32
+	LoudnessLUFS *float32
 }
 
 // ArtistRow — исполнитель со счётчиками.
@@ -58,8 +63,10 @@ const trackSelect = `
 		COALESCE((SELECT array_agg(g.name ORDER BY g.name) FROM track_genres tg JOIN genres g ON g.id = tg.genre_id
 			WHERE tg.track_id = t.id), '{}'),
 		EXISTS (SELECT 1 FROM media_files f JOIN library_sources s ON s.id = f.source_id
-			WHERE f.id = t.primary_file_id AND s.status = 'mounted')
+			WHERE f.id = t.primary_file_id AND s.status = 'mounted'),
+		tf.track_id IS NOT NULL, tf.bpm, tf.energy, tf.loudness_lufs
 	FROM tracks t
+	LEFT JOIN track_features tf ON tf.track_id = t.id
 	JOIN albums al ON al.id = t.album_id
 	JOIN artists aa ON aa.id = al.album_artist_id`
 
@@ -70,7 +77,8 @@ func scanTrack(row pgx.Row) (TrackRow, error) {
 	)
 	err := row.Scan(&t.ID, &t.Title, &t.DurationMs, &t.DiscNo, &t.TrackNo, &artists,
 		&t.Album.ID, &t.Album.Title, &t.Album.Year, &t.Album.CoverPath, &t.Album.CoverColors,
-		&t.Album.Artist.ID, &t.Album.Artist.Name, &t.Genres, &t.Available)
+		&t.Album.Artist.ID, &t.Album.Artist.Name, &t.Genres, &t.Available, &t.Analyzed, &t.BPM, &t.Energy,
+		&t.LoudnessLUFS)
 	if errors.Is(err, pgx.ErrNoRows) {
 		return TrackRow{}, ErrNotFound
 	}

services/api/internal/library/handler.go

@@ -362,10 +362,14 @@ func (d DTO) Track(t TrackRow) gen.Track {
 	if genres == nil {
 		genres = []string{}
 	}
-	return gen.Track{
+	out := gen.Track{
 		Id: t.ID, Title: t.Title, DurationMs: t.DurationMs, Artists: artists, Album: d.albumRef(t.Album),
 		Genres: genres, DiscNo: t.DiscNo, TrackNo: t.TrackNo, Available: t.Available,
 	}
+	if t.Analyzed {
+		out.Features = &gen.TrackFeatures{Bpm: t.BPM, Energy: t.Energy, LoudnessLufs: t.LoudnessLUFS}
+	}
+	return out
 }
 
 // AlbumSummary переводит альбом в схему AlbumSummary.