- The active payment window no longer accepts the old 15-minute format or
scans every order to bootstrap itself; a missing reservation means no window.
- Public link requests no longer need queue_protocol, unknown JSON fields are
ignored, and an empty cancel beacon is no longer treated as leaving.
- Checkout creation never charges, so a saved-card order whose creation failed
is retried on the next explicit request instead of being blocked forever;
creation still uses the safe retry helper within one request.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>