Get async vendor verification status/result

Retrieves the status and persisted result of a previously initiated async vendor verification request. The result field is null while the request is PENDING, carries the verification response body once COMPLETED, and carries error details when FAILED. The result is also delivered via the corresponding webhook (EKYB_VERIFICATION_RESULT / EKYC_VERIFICATION_RESULT); this endpoint is a read-only status check. Returns 404 if the referenceId is not found or belongs to a different tenant.