This endpoint enables clients to initiate the creation of a new user account. If a contact with an identical email address already exists, that contact will be elevated to the status of a registered user. Essential attributes like identifiers.email_address and validators.password are mandatory for this endpoint. If any of these attributes are absent, registration attempts will trigger an error. Upon a successful request, session cookies like blaize_session and blaize_tracking_id are generated and included in the response header.