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/scheduler/scheduler.py

@@ -21,7 +21,7 @@ class NewsScheduler:
     def __init__(self):
         self.scheduler = AsyncIOScheduler()
         self.mongodb_url = os.getenv("MONGODB_URL", "mongodb://mongodb:27017")
-        self.db_name = os.getenv("DB_NAME", "pipeline_db")
+        self.db_name = os.getenv("DB_NAME", "ai_writer_db")
         self.db = None
         self.queue_manager = QueueManager(
             redis_url=os.getenv("REDIS_URL", "redis://redis:6379")