feat(music-lab): pipeline 5개 DB 테이블 + 헬퍼

YouTube 음악 파이프라인 Task 1 — 신규 5개 테이블과 헬퍼 함수 추가.

테이블:
- video_pipelines: 파이프라인 단위 상태 머신 + 메타/리뷰 JSON
- pipeline_jobs: 단계별 비동기 작업 상태/시간
- pipeline_feedback: 텔레그램 피드백 이력
- youtube_oauth_tokens: 채널 OAuth refresh/access 토큰
- youtube_setup: 단일 행 설정 (메타 템플릿/커버 프롬프트/리뷰 가중치/임계값/비주얼/공개정책)

헬퍼:
- create_pipeline / get_pipeline / update_pipeline_state / list_pipelines
- increment_feedback_count / record_feedback / get_feedback_history
- create_pipeline_job / update_pipeline_job / list_pipeline_jobs
- get_youtube_setup / update_youtube_setup
- upsert_oauth_token / get_oauth_token / delete_oauth_token

테스트:
- tests/test_pipeline_db.py: 7개 테스트 (생성/상태/피드백/잡/셋업/OAuth)
- tests/conftest.py: freezegun 기반 freezer fixture 추가
- requirements.txt: freezegun>=1.4 추가

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

music-lab/tests/conftest.py

@@ -1,7 +1,36 @@
 import pytest
 
+
 @pytest.fixture
 def tmp_db(tmp_path, monkeypatch):
     db_path = str(tmp_path / "test_music.db")
     monkeypatch.setattr("app.db.DB_PATH", db_path)
     return db_path
+
+
+@pytest.fixture
+def freezer():
+    """Minimal freezegun-based fixture providing `move_to(time)` to mimic
+    pytest-freezer's `freezer` fixture using only the `freezegun` package."""
+    from freezegun import freeze_time
+
+    class _Freezer:
+        def __init__(self):
+            self._ctx = None
+
+        def move_to(self, target):
+            if self._ctx is not None:
+                self._ctx.stop()
+            self._ctx = freeze_time(target)
+            self._ctx.start()
+
+        def stop(self):
+            if self._ctx is not None:
+                self._ctx.stop()
+                self._ctx = None
+
+    f = _Freezer()
+    try:
+        yield f
+    finally:
+        f.stop()

music-lab/tests/test_pipeline_db.py

@@ -0,0 +1,96 @@
+import os
+import tempfile
+import pytest
+from app import db
+
+
+@pytest.fixture
+def fresh_db(monkeypatch, tmp_path):
+    db_path = tmp_path / "music.db"
+    monkeypatch.setattr(db, "DB_PATH", str(db_path))
+    db.init_db()
+    return db_path
+
+
+def test_create_pipeline_inserts_row(fresh_db):
+    pid = db.create_pipeline(track_id=1)
+    row = db.get_pipeline(pid)
+    assert row["id"] == pid
+    assert row["state"] == "created"
+    assert row["track_id"] == 1
+    assert row["feedback_count_per_step"] == {}
+
+
+def test_update_pipeline_state_records_started_at(fresh_db, freezer):
+    pid = db.create_pipeline(track_id=1)
+    freezer.move_to("2026-05-07T08:00:00")
+    db.update_pipeline_state(pid, "cover_pending")
+    row = db.get_pipeline(pid)
+    assert row["state"] == "cover_pending"
+    assert row["state_started_at"] == "2026-05-07T08:00:00"
+
+
+def test_increment_feedback_count(fresh_db):
+    pid = db.create_pipeline(track_id=1)
+    db.increment_feedback_count(pid, "cover")
+    db.increment_feedback_count(pid, "cover")
+    row = db.get_pipeline(pid)
+    assert row["feedback_count_per_step"] == {"cover": 2}
+
+
+def test_record_feedback(fresh_db):
+    pid = db.create_pipeline(track_id=1)
+    db.record_feedback(pid, "cover", "더 어둡게")
+    rows = db.get_feedback_history(pid)
+    assert len(rows) == 1
+    assert rows[0]["feedback_text"] == "더 어둡게"
+
+
+def test_create_pipeline_job_lifecycle(fresh_db):
+    pid = db.create_pipeline(track_id=1)
+    job_id = db.create_pipeline_job(pid, "cover")
+    db.update_pipeline_job(job_id, status="running")
+    db.update_pipeline_job(job_id, status="succeeded", duration_ms=1234)
+    jobs = db.list_pipeline_jobs(pid)
+    assert jobs[0]["status"] == "succeeded"
+    assert jobs[0]["duration_ms"] == 1234
+
+
+def test_youtube_setup_default_row_created_on_init(fresh_db):
+    setup = db.get_youtube_setup()
+    assert setup["review_threshold"] == 60
+    assert "metadata_template_json" in setup
+
+
+def test_youtube_oauth_token_upsert(fresh_db):
+    db.upsert_oauth_token(
+        channel_id="UC123",
+        channel_title="My Channel",
+        avatar_url="https://...",
+        refresh_token="r1",
+        access_token="a1",
+        expires_at="2026-05-07T09:00:00",
+    )
+    tok = db.get_oauth_token()
+    assert tok["channel_id"] == "UC123"
+    assert tok["refresh_token"] == "r1"
+    db.upsert_oauth_token(
+        channel_id="UC123", channel_title="My Channel",
+        avatar_url=None, refresh_token="r2",
+        access_token="a2", expires_at="2026-05-07T10:00:00",
+    )
+    tok = db.get_oauth_token()
+    assert tok["refresh_token"] == "r2"  # upsert
+
+
+def test_update_pipeline_state_rejects_unknown_column(fresh_db):
+    pid = db.create_pipeline(track_id=1)
+    with pytest.raises(ValueError):
+        db.update_pipeline_state(pid, "cover_pending", evil_col="x; DROP TABLE")
+
+
+def test_update_pipeline_job_rejects_unknown_column(fresh_db):
+    pid = db.create_pipeline(track_id=1)
+    job_id = db.create_pipeline_job(pid, "cover")
+    with pytest.raises(ValueError):
+        db.update_pipeline_job(job_id, evil_col="x")