A Slack user/legacy token (xoxp-...) makes auth.test resolve to the
installing human's member ID with no bot_id, so the adapter binds its
identity (_bot_user_id / _team_bot_user_ids) to that human. Every
"is this the bot?" check then misfires: that person's <@...> mentions
wake the bot and are stripped as the bot's own mention, so the agent is
genuinely told it was @mentioned and replies to messages merely
addressed to that human (symptom: bot responds to "@trevor ..." and
insists it was explicitly mentioned).
There is no runtime API error to catch — a user token still
sends/receives — so the only detectable moment is connect time. Add a
warning-only nudge (_warn_if_not_bot_token) alongside the existing
group-DM scope nudge: when auth.test resolves a user_id but no bot_id,
log that the token is a user token and to use the xoxb-... Bot User
OAuth Token. Warning-only: does not block a working-but-misconfigured
install. Fires once per workspace per process.
