post
https://apis.kentro.live/store/v1/payments.status
Where a change stands: by operationId, or, without one, the buyer's pending change if any (state: "idle" when there is none). A change still deciding is checked with the provider; complete or rejected are final.
Who may call it: A signed-in buyer (X-Storefront-Buyer); without one the answer is 401 UNAUTHORIZED.
