On the relay lane a Slack DM's streamed reply was sent with reply_to=the
triggering message ts; the connector maps a raw reply_to to a Slack thread_ts,
so the DM reply posted threaded under the user's message and lost progressive
edit-streaming (flat reply, no thinking status). Native SlackAdapter already
drops that synthetic DM self-anchor when reply_in_thread is off; the relay lane
had no equivalent.
Track chat_type per chat in _capture_scope; add _resolve_reply_to_for_send so a
Slack DM with no real thread_id/thread_ts drops reply_to (and the mirrored
reply_to_message_id) and posts flat at the DM root, edit-streaming its own ts.
Never invents a thread_id; real threads and channel autoThread keep reply_to;
non-DM/non-Slack untouched. Adapted to main's phase-3 prompt architecture.
Victor Kyriazakos
15d65da5a2