curl --request GET \
  --url http://localhost:8080/api/stats \
  --header 'Authorization: Bearer <token>'

{
  "chat_id": 123,
  "total_messages": 123,
  "total_users": 123,
  "messages_today": 123,
  "top_users": [
    {
      "user_id": 123,
      "username": "<string>",
      "message_count": 123
    }
  ]
}