Queue comments received while a run is active, then submit one deduplicated follow-up after it finishes. Failed drains are requeued and watcher tasks stop cleanly with the channel manager.
Adds two focused architecture docs and references from backend/AGENTS.md: - backend/docs/IM_CHANNEL_CONNECTIONS.md — sequence + graph diagrams for user-owned IM channel connections: bind-code flow (/connect/<start), single-active-owner transfer, provider message routing, owner-scoped file storage. - backend/docs/GITHUB_AGENTS.md — sequence + graph diagrams for GitHub event-driven agents: webhook fan-out, preferred_thread_id = UUID5, GH token lifecycle, race recovery. Co-authored-by: Claude <noreply@anthropic.com>
