feat: add operations health and domain setup polish

backend/app/services/cloudflare_dns.py

@@ -5,7 +5,7 @@ from __future__ import annotations
 import hashlib
 import json
 from dataclasses import dataclass
-from datetime import UTC, datetime
+from datetime import datetime, timezone
 from typing import Any, Dict, List, Optional
 
 from sqlalchemy.orm import Session
@@ -33,7 +33,7 @@ class CloudflareCredentials:
 
 
 def _utcnow_naive() -> datetime:
-    return datetime.now(UTC).replace(tzinfo=None)
+    return datetime.now(timezone.utc).replace(tzinfo=None)
 
 
 def _plain_setting_value(db: Session, key: str) -> Optional[str]: