fix: improve logging and pagination logic in delete_old_messages function

main.py

@@ -539,17 +539,11 @@ def delete_old_messages(minutes: int = 6) -> None:
             headers, DISCORD_CHANNEL_ID, webhook_id, author_id, cutoff, last_message_id
         )
 
-        # Exit loop if no more messages to delete
+        # Stop scanning when a page has no eligible messages to delete.
+        # Continuing pagination here can walk indefinitely through history.
         if not delete_list:
             if deleted_count == 0:
-                if next_last_message_id is None or next_last_message_id == last_message_id:
                 logging.info("No messages to delete.")
-                    break
-                else:
-                    logging.info(
-                        "No messages deleted in this batch, but more messages may exist... Continuing pagination.")
-                    last_message_id = next_last_message_id
-                    continue
             else:
                 logging.info("No more messages to delete.")
             break