5871d750bf
The room-level test is the reported defect: two composer sends, two threads, and neither backend transcript may contain the other thread's prompt. Proven red on the unfixed code — both threads resolved to sid-research-1. Also pins same-thread continuity, the pre-thread adoption (first thread continues the old conversation, later threads do not), and that the member half of the key stays source-qualified so a remote `research` and a local `research` never share a session. Co-authored-by: Wenfengcheng <30426178+Wenfengcheng@users.noreply.github.com>