feat: hyperlinks, group seen-by for all, profile-pic preview, in-call invite fix + desktop update progress (0.1.6)

- #1: URLs in chat are now clickable links (open externally on desktop).
- #2: group 'Seen by X, Y +N more' now shows under the LATEST message to EVERYONE
  (server computes reads for all messages; click shows the names).
- #5: tapping the conversation-header avatar previews the DP/group photo full-size.
- #4: in-call invite lists only people you've messaged, excludes those already in the
  call/invited, and the Invite button is sticky.
- #3 (0.1.6 shell): auto-updater emits checking/available/downloading/ready/error to
  the web UI, which shows a progress banner (+ Restart button) so updates aren't silent.

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

desktop/preload.js

@@ -25,4 +25,8 @@ contextBridge.exposeInMainWorld('bizConnectNative', Object.freeze({
   // Manual "Check for updates" from Settings. Resolves {status:'available'|'current'|'dev'|'error', version?}.
   // On 'available' the shell downloads in the background and prompts to restart when ready.
   checkForUpdates: () => ipcRenderer.invoke('check-updates'),
+  // #3: subscribe to auto-update lifecycle events so the UI can show download progress + "ready".
+  // cb receives {phase:'checking'|'available'|'downloading'|'ready'|'current'|'error', percent?, version?}.
+  onUpdateEvent: (cb) => { try { ipcRenderer.on('update-event', (_e, data) => { try { cb(data); } catch (_) {} }); } catch (_) {} },
+  restartToUpdate: () => ipcRenderer.invoke('restart-to-update'),
 }));