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/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@insignia/iios-messaging-ui",
-  "version": "0.1.6",
+  "version": "0.1.7",
   "type": "module",
   "main": "dist/index.js",
   "module": "dist/index.js",