Migrate blockchain-node app to centralized aitbc package utilities

- Migrate 10 files from logging to aitbc.get_logger
- combined_main.py, p2p_network.py, chain_sync.py
- network/bridge_manager.py, network/island_manager.py, network/nat_traversal.py
- network/multi_chain_manager.py, network/hub_manager.py, network/hub_discovery.py
- Remove logging.basicConfig() from combined_main.py
- Migrate hardcoded paths in config.py and hub_manager.py to use DATA_DIR and KEYSTORE_DIR constants

apps/blockchain-node/src/aitbc_chain/chain_sync.py

@@ -6,11 +6,12 @@ Keeps blockchain nodes synchronized by sharing blocks via P2P and Redis gossip
 
 import asyncio
 import json
-import logging
 import time
 from typing import Dict, Any, Optional, List
 
-logger = logging.getLogger(__name__)
+from aitbc import get_logger
+
+logger = get_logger(__name__)
 
 # Import settings for configuration
 try: