fix: seen-by layout, group-name notif, teams-style badge, excel paste, spellcheck (0.1.11/batch64)

1. Message-info popup: ONE scroll region for the whole list with sticky
   Seen / Not-seen headers (was a separate scrollbar per section), realigned.
2. Group message notifications now title = GROUP name, body = "Sender: text".
3. Unread taskbar badge: solid red rounded-square (Teams-style) + white outline
   instead of the gradient disc.
4. Pasting Excel/Sheets cells no longer uploads a screenshot — when the clipboard
   carries real text, the text is pasted; image-only clipboards still upload.
5. Spell check in the message box (red squiggles) with a right-click menu of
   corrections + add-to-dictionary; spellcheck enabled on the textarea.

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

desktop/package.json

@@ -1,6 +1,6 @@
 {
   "name": "biz-connect-desktop",
-  "version": "0.1.10",
+  "version": "0.1.11",
   "description": "Biz Connect technician desktop client — loads the Connect web UI with native screen capture",
   "author": {
     "name": "BizGaze",