getUpdates 秒回空包时 completed→立即续链 会退化成热循环，打满 Mongo/Redis 拖垮同进程登录页并刷屏日志。改为：有消息立即续链，无消息（空响应）延迟 10s 再续链。 Co-authored-by: Cursor <cursoragent@cursor.com>
