answerCallback wraps only its first callback switch in an isAdmin guard; the
second switch (server usage, inbound/online enumeration, database backup export,
ban logs, mass traffic reset, client creation) ran for every caller. Telegram
delivers a callback with the tapping user's id, so a non-admin who can see an
admin's inline keyboard — as when the bot runs in a group — could tap Backup and
receive the full database and config, or reset all traffic. Default-deny before
the second switch: a non-admin may only run the per-user client_* callbacks that
resolve their own data from their Telegram id.
MHSanaei