Manage scheduled posts. action=add creates a scheduled draft on a date (YYYY-MM-DD, tenant timezone, at the tenant's default publish time); update patches an existing one (date, caption, post type, approval mode, slides, recurrence); remove cancels it (soft-delete); bulk_fill generates AI drafts for each empty day in the next N days. Carousels need 2-10 slides. A draft created with a date posts at that date's publish time (approval_mode=scheduled, the default when none is given); pass approval_mode=email to have it wait for the owner's explicit publish_draft call or tap instead, approval_mode=auto to publish it at that time, or approval_mode=warning to publish it at that time after emailing the owner a cancel link about 24h before. Set auto or warning only when the owner asked for it: choosing one is their approval of that post. Scheduling is refused with scheduling_not_available where timed publishing is not enabled for the account.