Wave-based onboarding makes the auto-invite + polling path obsolete.
- Removes SlackService.inviteUserToSlack — admins now send invites
through Slack's UI and flip the flag in our admin endpoint.
- Removes the slack_invite_failed admin alert + its detector. The
alert no longer has a meaningful trigger (we don't attempt invites).
- Archives server/utils/checkSlackJoins.js (and its test) under
_archive/ in case the polling pattern is needed again post-pilot.
- Deletes the Nitro plugin that scheduled checkSlackJoins on boot
+ hourly. Nothing in nitro.config / nuxt.config / package.json
registered it elsewhere.
- Drops the slack_invite_failed branch from adminAlerts.test; the
enum slug stays in adminAlertDismissal so historical dismissal
rows continue to validate.
notifyNewMember (vetting-channel notification) and findUserByEmail
(used by the auto-flag helper) are retained.
Best-effort lookup of an activating member's email in the Slack
workspace. On a hit, flips slackInvited:true and stamps slackInvitedAt
without sending a fresh invite. Races against a 3s timeout and swallows
all errors so activation never blocks on Slack.
- Promotes SlackService.findUserByEmail from private to public so the
helper can call it without a wrapper.
- New activity-log action: slack_access_auto_detected (actor = subject).
- Idempotent: short-circuits when slackInvited is already true.
Callers wired in next commit.
