Move Fail2Ban exceptions into central app.exceptions module

backend/app/routers/jails.py

@@ -40,7 +40,7 @@ from app.models.jail import (
     JailListResponse,
 )
 from app.services import jail_service
-from app.utils.fail2ban_client import Fail2BanConnectionError
+from app.exceptions import Fail2BanConnectionError
 
 router: APIRouter = APIRouter(prefix="/api/jails", tags=["Jails"])