Hand Mirror 1.1.6

Add in-app auto-update (notify + one-click) via GitHub Releases

- UpdateService: checks the repo's latest GitHub Release, compares to the
  running assembly version, downloads the installer, and launches it
  silently (the installer kills + upgrades + relaunches us).
- TrayApp: checks on launch and every 30 min; shows a tray balloon and an
  "Install update X" menu item when a newer build exists. Clicking either
  downloads and applies it. Balloon only pops once per version.
- Installer: add a silent-mode [Run] relaunch so the app comes back after
  an unattended update.
- CI: version each build 1.1.<run_number> (monotonic) and publish a
  GitHub Release with the installer on every push to main, marked latest.
  Dropped the tag trigger (releases are now created by the build).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>