Closes the KYB for a business entity: checks the case is complete, locks the stored payload, and queues it for compliance review. Takes no request body — everything being submitted was already stored by POST/PATCH /entity/{entityId}/ukyb and POST /entity/{entityId}/ukyb/documents.

Completeness covers the mapped KYB documents, every mandatory field on each declared beneficial owner, and — per owner — that an identity document has been uploaded whose kind matches the one declared. Presence is what is checked, not approval: a document still under review, or previously rejected, does not block submission.

Once accepted the payload is locked: further POST/PATCH /ukyb and POST /ukyb/documents calls are rejected, and a repeat submit returns 409. Processing is asynchronous — the 202 means the case was accepted for review, not that review has finished.