feat(music-lab): video_pipelines 4 컬럼 추가 + compile_jobs JOIN

- _add_column_if_missing 헬퍼 추가 (idempotent ALTER TABLE)
- video_pipelines에 compile_job_id, visual_style, background_mode, background_keyword 컬럼 추가
- track_id를 nullable로 변경 (compile_job_id 입력 모드 지원)
- create_pipeline에 compile_job_id XOR track_id 검증 추가
- get_pipeline / list_pipelines에 compile_jobs LEFT JOIN — compile_title 노출

Task 1 of 17: Essential Mix pipeline DB migration

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

music-lab/tests/test_pipeline_db.py

@@ -94,3 +94,129 @@ def test_update_pipeline_job_rejects_unknown_column(fresh_db):
     job_id = db.create_pipeline_job(pid, "cover")
     with pytest.raises(ValueError):
         db.update_pipeline_job(job_id, evil_col="x")
+
+
+def test_create_pipeline_with_compile_job(fresh_db):
+    pid = db.create_pipeline(track_id=None, compile_job_id=42,
+                              visual_style="essential", background_mode="static",
+                              background_keyword="rainy cafe")
+    row = db.get_pipeline(pid)
+    assert row["track_id"] is None
+    assert row["compile_job_id"] == 42
+    assert row["visual_style"] == "essential"
+    assert row["background_mode"] == "static"
+    assert row["background_keyword"] == "rainy cafe"
+
+
+def test_create_pipeline_with_track_keeps_defaults(fresh_db):
+    pid = db.create_pipeline(track_id=1)
+    row = db.get_pipeline(pid)
+    assert row["track_id"] == 1
+    assert row["compile_job_id"] is None
+    assert row["visual_style"] == "essential"  # default
+    assert row["background_mode"] == "static"  # default
+    assert row["background_keyword"] is None
+
+
+def test_create_pipeline_rejects_neither(fresh_db):
+    import pytest
+    with pytest.raises(ValueError):
+        db.create_pipeline()
+
+
+def test_create_pipeline_rejects_both(fresh_db):
+    import pytest
+    with pytest.raises(ValueError):
+        db.create_pipeline(track_id=1, compile_job_id=2)
+
+
+def test_migration_idempotent(monkeypatch, tmp_path):
+    """init_db 두 번 호출해도 ALTER TABLE 에러 없이 통과."""
+    db_path = tmp_path / "music.db"
+    monkeypatch.setattr(db, "DB_PATH", str(db_path))
+    db.init_db()
+    db.init_db()  # 두 번째 — 컬럼 이미 존재해도 OK여야
+    import sqlite3
+    conn = sqlite3.connect(str(db_path))
+    cols = [r[1] for r in conn.execute("PRAGMA table_info(video_pipelines)").fetchall()]
+    assert "compile_job_id" in cols
+    assert "visual_style" in cols
+    assert "background_mode" in cols
+    assert "background_keyword" in cols
+    conn.close()
+
+
+def test_pipeline_response_includes_compile_title(fresh_db):
+    """compile_jobs LEFT JOIN — pipeline 응답에 compile_title 포함."""
+    import sqlite3
+    conn = sqlite3.connect(db.DB_PATH)
+    cur = conn.cursor()
+    cur.execute("""CREATE TABLE IF NOT EXISTS compile_jobs (
+        id INTEGER PRIMARY KEY AUTOINCREMENT, title TEXT, status TEXT,
+        track_ids_json TEXT, crossfade_sec INTEGER, audio_path TEXT, created_at TEXT)""")
+    cur.execute("INSERT INTO compile_jobs (id, title, status) VALUES (1, 'My Mix', 'succeeded')")
+    conn.commit()
+    conn.close()
+    pid = db.create_pipeline(compile_job_id=1)
+    p = db.get_pipeline(pid)
+    assert p.get("compile_title") == "My Mix"
+
+
+def test_migration_relaxes_existing_not_null_track_id(monkeypatch, tmp_path):
+    """기존 production-like DB(track_id NOT NULL)를 nullable로 마이그레이션."""
+    db_path = tmp_path / "music.db"
+    monkeypatch.setattr(db, "DB_PATH", str(db_path))
+
+    # 1) 옛 스키마(track_id NOT NULL)로 직접 생성
+    import sqlite3
+    conn = sqlite3.connect(str(db_path))
+    conn.execute("""
+        CREATE TABLE video_pipelines (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            track_id INTEGER NOT NULL,
+            state TEXT NOT NULL DEFAULT 'created',
+            state_started_at TEXT NOT NULL,
+            cover_url TEXT,
+            video_url TEXT,
+            thumbnail_url TEXT,
+            metadata_json TEXT,
+            review_json TEXT,
+            youtube_video_id TEXT,
+            feedback_count_per_step TEXT NOT NULL DEFAULT '{}',
+            last_telegram_msg_ids TEXT NOT NULL DEFAULT '{}',
+            created_at TEXT NOT NULL,
+            updated_at TEXT NOT NULL,
+            cancelled_at TEXT,
+            failed_reason TEXT
+        )
+    """)
+    # 옛 데이터 1행
+    conn.execute("""
+        INSERT INTO video_pipelines (track_id, state_started_at, created_at, updated_at)
+        VALUES (1, '2026-05-01T00:00:00', '2026-05-01T00:00:00', '2026-05-01T00:00:00')
+    """)
+    conn.commit()
+    conn.close()
+
+    # 2) init_db 실행 (마이그레이션 트리거)
+    db.init_db()
+
+    # 3) NOT NULL 제약 해제 확인
+    conn = sqlite3.connect(str(db_path))
+    cur = conn.cursor()
+    cur.execute("PRAGMA table_info(video_pipelines)")
+    cols = {r[1]: r[3] for r in cur.fetchall()}  # name → notnull
+    assert cols["track_id"] == 0  # not null released
+    # 새 컬럼들도 존재
+    assert "compile_job_id" in cols
+    assert "visual_style" in cols
+    # 기존 데이터 보존
+    cur.execute("SELECT track_id FROM video_pipelines WHERE id=1")
+    assert cur.fetchone()[0] == 1
+    conn.close()
+
+    # 4) compile_job_id-only INSERT 가능 확인
+    pid = db.create_pipeline(compile_job_id=99)
+    p = db.get_pipeline(pid)
+    assert p["track_id"] is None
+    assert p["compile_job_id"] == 99