feat: Implement automated keyword-based news pipeline scheduler

- Add multi-threaded keyword scheduler for periodic news collection
- Create Keyword Manager API for CRUD operations and monitoring
- Implement automatic pipeline triggering (RSS → Google → AI → Translation)
- Add thread status monitoring and dynamic keyword management
- Support priority-based execution and configurable intervals
- Add comprehensive scheduler documentation guide
- Default keywords: AI, 테크놀로지, 경제, 블록체인

🤖 Generated with [Claude Code](https://claude.ai/code)

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

services/pipeline/monitor/monitor.py

@@ -46,7 +46,7 @@ async def startup_event():
     # MongoDB 연결
     mongodb_url = os.getenv("MONGODB_URL", "mongodb://mongodb:27017")
     mongodb_client = AsyncIOMotorClient(mongodb_url)
-    db = mongodb_client[os.getenv("DB_NAME", "pipeline_db")]
+    db = mongodb_client[os.getenv("DB_NAME", "ai_writer_db")]
     
     logger.info("Pipeline Monitor started successfully")