The trigger creates the order before it notifies, so the backend reads back
the order the notification is about. A transition moves the stored order
and emits the notification that platform would emit —
order/cancelled on Nuvemshop, order.status.updated
plus a status id on Yampi, act=update on Tray.
A rule answers the matching platform-API call instead of the handler, with
that platform's own error body. It is how the backend's 401 → reconnect,
429 → Retry-After and 5xx → retry paths are exercised
without waiting for the platform to misbehave.