A third-party backend uses an access token to create a one-time editor code for an end user.

The server finds or creates the end user by (applicationId, userId). userId is the caller's end-user ID, not the internal ss_user.id. Optional non-blank name, email, and phone values update the stored end-user profile; omitted, null, or empty values preserve existing profile values.

This endpoint only returns the minimal data needed for editor login redirection. The third-party redirects the browser to the ss editor frontend with this code; the frontend consumes the code internally and completes end-user login. This endpoint does not return applicationId, endUserId, created, or an internal user object.