fix: replace deprecated datetime.utcnow with timezone-aware datetime.now in all modules and fix comment count query column name

devplacepy/attachments.py

@@ -1,5 +1,5 @@
 import logging
-from datetime import datetime
+from datetime import datetime, timezone
 from pathlib import Path
 from PIL import Image
 from io import BytesIO
@@ -74,7 +74,7 @@ def store_attachment(file_bytes, original_filename, user_uid):
         "directory": directory, "file_size": len(file_bytes), "mime_type": mime,
         "image_width": img_w, "image_height": img_h,
         "has_thumbnail": 1 if thumb else 0,
-        "created_at": datetime.utcnow().isoformat(),
+        "created_at": datetime.now(timezone.utc).isoformat(),
     })
     return {"uid": uid, "original_filename": original_filename, "file_size": len(file_bytes), "mime_type": mime, "url": f"/static/uploads/attachments/{directory}/{stored_name}", "thumbnail_url": f"/static/uploads/attachments/{directory}/{thumb}" if thumb else None, "has_thumbnail": thumb is not None, "is_image": is_img}