Final review findings:
- Wrap the operator-approval copy/drop/rename in a single immediate
transaction so a crash mid-migration cannot strand or lose rows.
- The inference fallback marked a provider attempted before probing, so a
stale requester credential blocked another agent's valid same-provider
route. Dedup by credential owner and only retire a whole provider on
provider-wide failures (auth/billing may differ per credential owner).
Refs #107237
Peter Steinberger
30bbe1b385