message-demo gains a per-person Inbox rail (useInbox, done/snooze); sending
surfaces a NEEDS_REPLY item in the other pane; reading auto-resolves it.
smoke-inbox.mjs proves the event-driven flow end-to-end (send -> relay ->
projector -> inbox -> read -> DONE). Realtime smoke still passes.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
