feat(agent-office): service_proxy pipeline_retry/list_failed_pipelines (+ music-lab status=failed 필터)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

music-lab/tests/test_pipeline_endpoints.py

@@ -52,6 +52,19 @@ def test_list_pipelines_active_filter(client):
     assert all(p["state"] != "published" for p in r.json()["pipelines"])
 
 
+def test_list_pipelines_failed_filter(client):
+    """status=failed 필터는 state='failed' 파이프라인만 반환한다."""
+    # failed 파이프라인 생성
+    pid_f = client.post("/api/music/pipeline", json={"track_id": 1}).json()["id"]
+    db.update_pipeline_state(pid_f, "failed", failed_reason="cover: oops")
+    r = client.get("/api/music/pipeline?status=failed")
+    assert r.status_code == 200
+    pipelines = r.json()["pipelines"]
+    assert len(pipelines) == 1
+    assert pipelines[0]["state"] == "failed"
+    assert pipelines[0]["id"] == pid_f
+
+
 def test_feedback_reject_records_feedback_and_increments_count(client):
     pid = client.post("/api/music/pipeline", json={"track_id": 1}).json()["id"]
     db.update_pipeline_state(pid, "cover_pending")