Move Fail2Ban exceptions into central app.exceptions module

backend/tests/test_services/test_jail_service.py

@@ -13,7 +13,7 @@ from app.models.geo import GeoDetail, GeoInfo
 from app.models.jail import JailDetailResponse, JailListResponse
 from app.services import jail_service
 from app.services.jail_service import JailNotFoundError, JailOperationError
-from app.utils.fail2ban_client import Fail2BanConnectionError
+from app.exceptions import Fail2BanConnectionError
 
 # ---------------------------------------------------------------------------
 # Helpers