plans: names cancel never answers open

plans/names-codes/2026-10-21-store-api.md

@@ -339,7 +339,7 @@ The duration uses the code's `years`. Checks, in order:
 ### `POST /api/invoice/:id/cancel`
 
 As for badges, with the name's view:
-- `200` the invoice view, now `expired` (or still `open` when the provider took the cancel late: the page shows "still open" and keeps the order);
+- `200` the invoice view, now `expired`. The service cancels at the provider first and expires its record only after the provider accepted, so a cancel never answers `open`;
 - `409 not_open`, `409 funded` (the service has read a payment), `404 not_found`, `503 provider_unavailable` (also when Stripe refuses to cancel an intent already processing).
 
 A cancel that lost to settlement answers `200` with `status: paid`; the page re-reads and opens the registration.