Creates a business-scoped landing page using the same page creation behavior as Landing Page Studio. The request body below documents the HTML Mode payload. To create and publish an HTML Mode page in one call, include is_published: true with page_display. If is_published is omitted or false, the nested page_display is saved as an unpublished draft and is not returned as the page's current display; create or pick a page display, then call PATCH /v3/pages/{id} with is_published: true and current_page_display_id to publish it.