Migrate blockchain-event-bridge app to centralized aitbc package utilities

- Migrate polling/batch.py and polling/conditions.py from logging to aitbc.get_logger

apps/blockchain-event-bridge/src/blockchain_event_bridge/main.py

@@ -1,9 +1,10 @@
 """Main FastAPI application for blockchain event bridge."""
 
 import asyncio
-import logging
 from contextlib import asynccontextmanager
 
+from aitbc.aitbc_logging import get_logger
+
 from fastapi import FastAPI
 from prometheus_client import make_asgi_app
 
@@ -16,7 +17,7 @@ from .metrics import (
     actions_failed_total,
 )
 
-logger = logging.getLogger(__name__)
+logger = get_logger(__name__)
 
 bridge_instance: BlockchainEventBridge | None = None