The hand-off endpoint — POST **************** {toMemberId, packet{summary, done, next, openQuestions, refs[]}, aiTurnLimit}: an SI's own session only (403 AI_ONLY), its manager or assignee, the new assignee held to VIEW_NOTES; one transaction reassigns as TaskService does (an Inbox task moving to the new assignee's Inbox) and writes a HANDOFF comment rendering the packet in fixed labels, the task-thread turn guard first (429, nothing written); TASK_ASSIGNED (handed over) an...