Trigger a return-poll catch-up drain
Derives the participants awaiting a return for the request tenant and drives the ProcessReturn pipeline (poll PRO/RET → correlate → transition) once per participant, the same work the schedule worker runs. RBAC: connectivity:admin. INBOUND and NOT window-gated. It drives the idempotent ProcessReturn pipeline, so it runs lock-free and is safe to run concurrently with the worker.
POST
Trigger a return-poll catch-up drain
Authorizations
JWT bearer token issued by the identity provider.

