Partner embed and onboarding guides

Partners integrating with e-Próspera residency onboarding now have three dedicated guides:

• Partner Keys remains the API contract and now documents residency types, field formats, referral codes, every create, update, upload, payment, and submission error body, the checkout providers and response shape, voucher error codes, and the statusId lifecycle.
• Embedded agreement and identity verification is a new guide to the PKCE-bound iframe: embed origins per environment, Content Security Policy, the 201 response, the 30-second activation window, the event and state contract, every SESSION_EXPIRED cause, the top-level Veriff fallback, and the error catalog for session creation.
• Partner onboarding is a new guide to provisioning: what to send e-Próspera, origin rules, key rotation and suspension, security responsibilities, the pre-production checklist, and how to report problems.

Testing in staging adds partner-specific staging behavior, including automatic approval and how Veriff decisions are simulated. Conventions corrects the voucher response envelope for partner applications and the note on date-only fields.

Reference changes

The generated reference now lists per-operation error responses for the partner endpoints, marks Idempotency-Key as required on application creation, checkout, and voucher payment, and describes the Idempotency-Replayed response header. The voucher operation's response schema now matches the application envelope the endpoint actually returns.