The email-thread turn guard and the primary address — an SI's reply carrying aiTurnLimit (1-100) is refused 429 AI_TURN_LIMIT when the thread's newest limit messages in its mailbox are all by SI members (AiReplyTurnGuard; a person's field ignored, fails open with a WARN), and GET **************** answers the member's primary mailbox in the org, with the member_mailboxes(member_id) index DDL (KamoCollab CP12 Task 15)