Post Thread Rejoin

Send the bot back into this thread's meeting, exactly as it went last time.

A meeting whose call has ended left the operator nothing: the header keeps only the "Open in Google Meet" link, because every live control is gated on an active call. Repeating the dispatch meant leaving the thread, finding the context menu, and re-entering agent, spoken language, translation, target language, voice and vision mode by hand — for a bot that had just been running with all of them.

The settings are already here. voice_sessions keeps the row after the call (status='ended') and its metadata holds what the dispatch was given, so this reconstructs the request SERVER-side. The browser sends a thread id and nothing else — it never learns the metadata-to-parameters mapping and so cannot get it subtly wrong.

404 with no previous session, 409 while one is still running. Capacity, a since-deleted agent and spawn failure keep the errors _create_and_spawn_meet_session already raises.