at.marque.partner.createCheckout

Prices and validates the requested domains, ensures a registrant contact for the authenticated user, and returns a hosted checkout URL. Call this proxied through the user's PDS (atproto-proxy: did:web:marque.at#marque_registrar) with a token holding the at.marque.partnerApi permission set: the authenticated user (the JWT iss) becomes the owner of the domains and is billed by the selected payment provider. The owning DID is taken from that authenticated session, never from input. The end user completes payment on the provider's hosted page and is redirected to successUrl with an order query parameter (successUrl?order=<orderId>) on success, or to cancelUrl if they abandon. Domains are not registered until payment is confirmed; poll at.marque.partner.getOrder with the returned orderId for provisioning status, then write the at.marque.domain and at.marque.dns records into the user's repository yourself. Only new registrations are supported here (no transfers or renewals).