A guardian finishing a connect for a managed profile could attach their
own provider account to the profile. Every OAuth callback (Withings,
WHOOP, Fitbit, Google Health, Strava, Polar, Oura) now refuses a
provider account another record already holds with reason
already_linked, shown as its own message on the integrations page.
WHOOP's owner_conflict tag becomes already_linked as well.
Oura keeps the account id of a grant (personal_info, migration 0441) so
the check has something to compare; existing connections fill it at
their next connect.
A disconnect leaves Withings webhook subscriptions and the Strava app
authorisation in place while another record holds the same account,
and the Withings webhook routes an account held twice to the record
that linked it first instead of whichever row a lookup returned.
The provider app copied from a guardian onto a managed profile is now
marked (migration 0442) and removed again on disconnect or when that
guardian no longer holds a live MANAGE grant: revoke, renounce,
removal, handover, account deletion and data wipe. Each removal is
audited as integration.client_app.removed.
