feat(rec): audio analyzer and My Wave v1 engine (M4)

- migration 00006: track features and embeddings (pgvector, HNSW),
  analysis queue filled by a trigger on new tracks, wave sessions and
  impressions, recommender profiles, model versions
- analyzer basic-1 (ADR-014): ffmpeg decode, three 30 s excerpts,
  256-d timbre/rhythm embedding, tempo by onset autocorrelation, key,
  loudness, energy, danceability, acousticness, intro length; worker
  with SKIP LOCKED claims, retries and re-analysis on version change
- wave engine v1: candidates (session/taste similarity, fresh,
  liked artists, rediscover, popular, exploration, seed), filters
  (dislikes, played in 3 h, already served), heuristic score, activity
  and mood fit from contexts.yaml with relaxing thresholds, MMR with
  one track per artist, exploration share, session vector updated by
  reactions and a change of course after three skips
- POST /internal/wave/batch with the catalog index cached in memory
  and the session kept in Redis

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

services/api/migrations/00006_wave.sql

@@ -0,0 +1,106 @@
+-- +goose Up
+CREATE TABLE track_features (
+  track_id         uuid PRIMARY KEY REFERENCES tracks(id) ON DELETE CASCADE,
+  analyzer_ver     text NOT NULL,
+  bpm              real,
+  bpm_confidence   real,
+  key              text,
+  scale            text,
+  loudness_lufs    real,
+  energy           real,
+  danceability     real,
+  valence          real,
+  arousal          real,
+  acousticness     real,
+  instrumentalness real,
+  mood_happy       real,
+  mood_sad         real,
+  mood_relaxed     real,
+  mood_aggressive  real,
+  mood_party       real,
+  intro_ms         int,
+  analyzed_at      timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE TABLE track_embeddings (
+  track_id   uuid PRIMARY KEY REFERENCES tracks(id) ON DELETE CASCADE,
+  audio      vector(256),
+  cf         vector(64),
+  updated_at timestamptz NOT NULL DEFAULT now()
+);
+CREATE INDEX track_embeddings_audio_idx ON track_embeddings USING hnsw (audio vector_cosine_ops);
+
+CREATE TABLE analysis_jobs (
+  track_id   uuid PRIMARY KEY REFERENCES tracks(id) ON DELETE CASCADE,
+  status     text NOT NULL DEFAULT 'queued',
+  attempts   int NOT NULL DEFAULT 0,
+  error      text,
+  updated_at timestamptz NOT NULL DEFAULT now()
+);
+CREATE INDEX analysis_jobs_queued_idx ON analysis_jobs (updated_at) WHERE status = 'queued';
+
+-- Каждый новый трек сразу встаёт в очередь анализа; существующие — тоже.
+-- +goose StatementBegin
+CREATE FUNCTION enqueue_analysis() RETURNS trigger LANGUAGE plpgsql AS $$
+BEGIN
+  INSERT INTO analysis_jobs (track_id) VALUES (NEW.id) ON CONFLICT DO NOTHING;
+  RETURN NEW;
+END $$;
+-- +goose StatementEnd
+CREATE TRIGGER tracks_enqueue_analysis AFTER INSERT ON tracks FOR EACH ROW EXECUTE FUNCTION enqueue_analysis();
+INSERT INTO analysis_jobs (track_id) SELECT id FROM tracks ON CONFLICT DO NOTHING;
+
+CREATE TABLE wave_sessions (
+  id            uuid PRIMARY KEY,
+  user_id       uuid NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+  activity      text,
+  mood          text,
+  seed_type     text,
+  seed_id       uuid,
+  started_at    timestamptz NOT NULL DEFAULT now(),
+  ended_at      timestamptz,
+  tracks_served int NOT NULL DEFAULT 0
+);
+CREATE INDEX wave_sessions_user_idx ON wave_sessions (user_id, started_at DESC);
+
+CREATE TABLE wave_impressions (
+  wave_session_id  uuid REFERENCES wave_sessions(id) ON DELETE CASCADE,
+  position         int NOT NULL,
+  track_id         uuid NOT NULL,
+  candidate_source text NOT NULL,
+  score            real,
+  model_ver        text,
+  served_at        timestamptz NOT NULL DEFAULT now(),
+  outcome          text,
+  PRIMARY KEY (wave_session_id, position)
+);
+CREATE INDEX wave_impressions_track_idx ON wave_impressions (wave_session_id, track_id);
+
+CREATE TABLE user_profiles_rec (
+  user_id     uuid PRIMARY KEY REFERENCES users(id) ON DELETE CASCADE,
+  taste_audio vector(256),
+  taste_cf    vector(64),
+  genre_prefs jsonb NOT NULL DEFAULT '{}',
+  bandit      jsonb NOT NULL DEFAULT '{}',
+  exploration real NOT NULL DEFAULT 0.15,
+  updated_at  timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE TABLE model_versions (
+  id         text PRIMARY KEY,
+  kind       text NOT NULL,
+  metrics    jsonb,
+  is_active  boolean NOT NULL DEFAULT false,
+  created_at timestamptz NOT NULL DEFAULT now()
+);
+
+-- +goose Down
+DROP TABLE model_versions;
+DROP TABLE user_profiles_rec;
+DROP TABLE wave_impressions;
+DROP TABLE wave_sessions;
+DROP TRIGGER tracks_enqueue_analysis ON tracks;
+DROP FUNCTION enqueue_analysis();
+DROP TABLE analysis_jobs;
+DROP TABLE track_embeddings;
+DROP TABLE track_features;