feat: implement timezone-aware logging system

- Fix inconsistent timestamp formats in logs for easier troubleshooting
- All logging systems now respect Docker TZ environment variable (e.g., TZ=America/New_York)
- Add TimezoneAwareFormatter for Python's standard logging module
- Enhance _log function with robust timezone support and fallbacks
- Replace placeholder logging functions with centralized core.logging._log
- Support both zoneinfo (Python 3.9+) and pytz (older versions)
- Users now see consistent timezone formatting across all log outputs

clients/external_clients.py

@@ -11,10 +11,7 @@ from urllib.parse import urlencode, quote
 from urllib.request import Request as UrlRequest, urlopen
 from urllib.error import URLError, HTTPError
 
-
-def _log(level: str, msg: str):
-    """Placeholder logging function - replace with your actual logger"""
-    print(f"[{datetime.now().isoformat()}] {level}: {msg}")
+from core.logging import _log
 
 
 def _get_json(url: str, timeout: int = 20, headers: Dict[str, str] = None) -> Optional[Dict[str, Any]]: