Claim pending rows atomically and serialize the sidecar poller so overlapping polls cannot send the same reply twice; also stop inbound queue delivery from falling through to a second enqueue.
Co-authored-by: Cursor <cursoragent@cursor.com>
Serialize per-session inbound turns and merge follow-ups after the active run; show composing while busy and enqueue final replies so long agent runs still reach the group.
Co-authored-by: Cursor <cursoragent@cursor.com>
