feat(messaging-ui): message timestamps + group/channel settings panel (0.1.5)

- Every message now shows a Slack-style time (clock today, then 'Yesterday',
  weekday, else a date; full timestamp on hover).
- New ConversationSettings panel for groups AND channels (public + private):
  rename, member list, add people (from the directory), remove, and leave.
  Opened from a new thread header gear; DMs show no gear. Adapter gains
  addMember/removeMember/renameConversation (optional, OPA still gates writes).

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": "0.1.4",
+  "version": "0.1.5",
   "type": "module",
   "main": "dist/index.js",
   "module": "dist/index.js",