feat(agent-office): youtube_publisher 에이전트 + 30s 폴링

- YoutubePublisherAgent: 음악 파이프라인의 *_pending 상태를 폴링하여
  텔레그램 단일 채널로 단계별 검토 요청 발송, reply 수신 시 의도 분류
  후 music-lab에 feedback POST
- service_proxy: pipeline list/get/feedback/telegram-msg/lookup-by-msg
  헬퍼 5종 추가 (MUSIC_LAB_URL 사용)
- scheduler: 30초 interval로 poll_state_changes 실행
- telegram webhook: reply_to_message 가 파이프라인 메시지면
  youtube_publisher 로 라우팅 (슬래시 명령보다 우선)
- 테스트 4종 추가 (4 PASS)

agent-office/tests/test_pipeline_polling.py

@@ -0,0 +1,110 @@
+import os
+import sys
+import tempfile
+
+_fd, _TMP = tempfile.mkstemp(suffix=".db")
+os.close(_fd)
+os.unlink(_TMP)
+os.environ["AGENT_OFFICE_DB_PATH"] = _TMP
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+
+import pytest
+from unittest.mock import AsyncMock, patch
+
+
+@pytest.fixture(autouse=True)
+def _init_db():
+    import gc
+    gc.collect()
+    if os.path.exists(_TMP):
+        os.remove(_TMP)
+    from app.db import init_db
+    init_db()
+    yield
+    gc.collect()
+
+
+@pytest.mark.asyncio
+async def test_poll_notifies_once_per_state():
+    from app.agents.youtube_publisher import YoutubePublisherAgent
+
+    pipelines = [{
+        "id": 1,
+        "state": "cover_pending",
+        "cover_url": "/x.jpg",
+        "track_title": "Test",
+    }]
+    with patch(
+        "app.agents.youtube_publisher.service_proxy.list_active_pipelines",
+        new=AsyncMock(return_value=pipelines),
+    ), patch(
+        "app.agents.youtube_publisher.send_raw",
+        new=AsyncMock(return_value={"ok": True, "message_id": 99}),
+    ) as mock_send, patch(
+        "app.agents.youtube_publisher.service_proxy.save_pipeline_telegram_msg",
+        new=AsyncMock(),
+    ):
+        a = YoutubePublisherAgent()
+        await a.poll_state_changes()
+        await a.poll_state_changes()  # 같은 상태 — 두 번째는 알림 안 함
+        assert mock_send.call_count == 1
+
+
+@pytest.mark.asyncio
+async def test_on_telegram_reply_approve_calls_feedback():
+    from app.agents.youtube_publisher import YoutubePublisherAgent
+
+    with patch(
+        "app.agents.youtube_publisher.service_proxy.post_pipeline_feedback",
+        new=AsyncMock(),
+    ) as mock_fb, patch(
+        "app.agents.youtube_publisher.send_raw",
+        new=AsyncMock(),
+    ):
+        a = YoutubePublisherAgent()
+        await a.on_telegram_reply(pipeline_id=42, step="cover", user_text="승인")
+        mock_fb.assert_called_once_with(42, "cover", "approve", None)
+
+
+@pytest.mark.asyncio
+async def test_on_telegram_reply_reject_with_feedback():
+    from app.agents.youtube_publisher import YoutubePublisherAgent
+
+    with patch(
+        "app.agents.youtube_publisher.service_proxy.post_pipeline_feedback",
+        new=AsyncMock(),
+    ) as mock_fb, patch(
+        "app.agents.youtube_publisher.send_raw",
+        new=AsyncMock(),
+    ):
+        a = YoutubePublisherAgent()
+        await a.on_telegram_reply(pipeline_id=43, step="meta", user_text="반려, 제목 짧게")
+        args = mock_fb.call_args[0]
+        assert args[0] == 43
+        assert args[1] == "meta"
+        assert args[2] == "reject"
+        assert "제목 짧게" in (args[3] or "")
+
+
+@pytest.mark.asyncio
+async def test_on_telegram_reply_unclear_asks_again():
+    from app.agents.youtube_publisher import YoutubePublisherAgent
+
+    sent = []
+
+    async def mock_send(text=None, **kw):
+        sent.append(text)
+        return {"ok": True, "message_id": 1}
+
+    with patch(
+        "app.agents.youtube_publisher.send_raw",
+        new=mock_send,
+    ), patch(
+        "app.agents.youtube_publisher.classify_intent.classify",
+        return_value=("unclear", None),
+    ):
+        a = YoutubePublisherAgent()
+        await a.on_telegram_reply(pipeline_id=44, step="cover", user_text="huh?")
+        assert any("다시 입력" in (s or "") for s in sent)