Treat a merged assistant-role summary carrier as the driving reference handoff when it immediately follows a completed assistant stop. Its preserved prose and stale tool_calls are assistant continuity, not a fresh live user request.
Keep legitimate in-flight behavior unchanged when there is no completed stop, a real user turn follows, or a distinct later assistant tool-call row continues the loop.
Extends the #80622 active-turn guard for the merged-carrier shape reported under #42768.
fdf0111410