fix: seen-by popup (#2), info-view DP preview (#5), notification DP cache + no Close btn, branded update flow (0.1.7)

- #2: 'Seen by' opens an on-screen popup listing readers (was a flash toast).
- #5: the DM contact-info view now shows the DP; clicking it previews full-size.
- Desktop notifications: cache DPs per-sender (fast AND with photo after the first);
  removed timeoutType:'never' which added an unwanted 'Close' button.
- Update flow: dropped the unbranded native restart dialog — the branded web banner
  handles Restart. Banner text clearer ('Downloading update…'), plus an update
  indicator that cascades profile 'i' badge → Settings → version line, with the
  Settings button becoming 'Restart now' when the update is downloaded. desktop 0.1.7.

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

desktop/package.json

@@ -1,6 +1,6 @@
 {
   "name": "biz-connect-desktop",
-  "version": "0.1.6",
+  "version": "0.1.7",
   "description": "Biz Connect technician desktop client — loads the Connect web UI with native screen capture",
   "author": {
     "name": "BizGaze",