Refund a captured booking payment when the operator rejects the booking

Adds a refund step on the rejection branch of the booking example workflow: a rejected booking with a captured payment is refunded before the release notification, and the notification mentions the refund only when an amount was returned. A second commit syncs the shipped BPMN diagram with the saved modeler layout (presentation only).

Depends on orchestra #3609403 (MR !305): the payment bridge must claim the refund event for token-pinned payments. That must land in orchestra 1.x before the functional test here passes in CI.

See #3609409.