fix(agent-office): YouTubeResearchAgent 품질 개선 (동시실행 가드·에러 로깅·타입 수정)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

agent-office/app/main.py

@@ -185,7 +185,7 @@ def activity_feed(limit: int = 50, offset: int = 0):
 # --- Realestate Agent Push Endpoint ---
 
 from pydantic import BaseModel
-from typing import List, Dict, Any
+from typing import List, Dict, Any, Optional
 
 
 class RealestateNotifyBody(BaseModel):
@@ -208,8 +208,8 @@ class YouTubeResearchBody(BaseModel):
 
 
 @app.post("/api/agent-office/youtube/research")
-async def trigger_youtube_research(body: YouTubeResearchBody = None):
-    agent = AGENT_REGISTRY.get("youtube")
+async def trigger_youtube_research(body: Optional[YouTubeResearchBody] = None):
+    agent = get_agent("youtube")
     if not agent:
         raise HTTPException(status_code=503, detail="YouTubeResearchAgent 없음")
     params = {}