Superuser-only: re-run the pricing_tiers.yaml sync synchronously
(TASK-S42-003), for edit-without-restart.
Identical logic to the leader-elected startup sync
(app.services.billing.catalog_sync.catalog_sync_loop) — this route
exists only to let an operator re-apply a price edit without restarting
the whole backend. It never fails the request for a refused sync (a
stale catalog_version or a validation error): those come back as
applied: false with a reason and errors, same posture as the
startup loop’s ERROR log — this is a result to report, not a server
fault.