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

devplacepy/routers/follow.py

@@ -1,5 +1,5 @@
 import logging
-from datetime import datetime
+from datetime import datetime, timezone
 from fastapi import APIRouter, Request
 from fastapi.responses import RedirectResponse
 from devplacepy.database import get_table
@@ -26,7 +26,7 @@ async def follow_user(request: Request, username: str):
         "uid": generate_uid(),
         "follower_uid": user["uid"],
         "following_uid": target["uid"],
-        "created_at": datetime.utcnow().isoformat(),
+        "created_at": datetime.now(timezone.utc).isoformat(),
     })
 
     notifications = get_table("notifications")
@@ -37,7 +37,7 @@ async def follow_user(request: Request, username: str):
         "message": f"{user['username']} started following you",
         "related_uid": user["uid"],
         "read": False,
-        "created_at": datetime.utcnow().isoformat(),
+        "created_at": datetime.now(timezone.utc).isoformat(),
     })
 
     logger.info(f"{user['username']} followed {username}")