feat(messaging-ui): presence + live-unread adapter seams

Add optional MessagingAdapter.setFocus(threadId) and subscribeActivity(cb)
so hosts can report the foregrounded thread (backend suppresses push for it)
and drive live conversation-list refresh on any thread's activity. Messenger
wires focus/blur presence + activity-driven refetch. Published as 0.1.7.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/iios-messaging-ui/src/components/messenger.tsx

@@ -40,6 +40,29 @@ export function Messenger({ focusThreadId }: { focusThreadId?: string | null } =
     setSelected(focusThreadId);
   }, [focusThreadId]);
 
+  // Presence: tell the backend which thread is foregrounded so it suppresses push for it. Null while
+  // browsing/composing, when the window is blurred, and on unmount (leaving the messenger).
+  useEffect(() => {
+    const active = browsing || composing ? null : selected;
+    adapter.setFocus?.(active);
+    const onBlur = (): void => adapter.setFocus?.(null);
+    const onFocus = (): void => adapter.setFocus?.(active);
+    window.addEventListener('blur', onBlur);
+    window.addEventListener('focus', onFocus);
+    return () => {
+      adapter.setFocus?.(null);
+      window.removeEventListener('blur', onBlur);
+      window.removeEventListener('focus', onFocus);
+    };
+  }, [adapter, selected, browsing, composing]);
+
+  // Live unread + ordering: refresh the conversation list when any of the caller's threads gets a
+  // message (not just the open one).
+  useEffect(() => {
+    if (!adapter.subscribeActivity) return;
+    return adapter.subscribeActivity(() => refetch());
+  }, [adapter, refetch]);
+
   const channels = useMemo(() => conversations.filter((c) => c.membership === 'channel'), [conversations]);
   const dms = useMemo(() => conversations.filter((c) => c.membership !== 'channel'), [conversations]);
   const selectedConversation = useMemo(() => conversations.find((c) => c.threadId === selected) ?? null, [conversations, selected]);