Snip 0.1.1

Updates through GitHub Releases (Velopack), as Total Git and Panehouse

- release.yml: on every push to main, test, publish self-contained, pack with vpk (packId SnipApp, so uninstalling
  never deletes %LOCALAPPDATA%\Snip) and upload a GitHub Release v0.1.<run>.
- UpdateService checks the releases 30 s after start and every 3 h, downloads in the background, and restarts into
  the update straight away when no editor is open and nothing is being captured; otherwise the tray offers "Restart
  to update", and Exit applies it.
- Velopack's install hook starts Snip at sign-in and turns off Windows' own Print Screen setting; the uninstall hook
  puts both back (WindowsSetup, which the tray's Start with Windows now uses too).
- The tray shows the version.
- A test's broker host is a made-up one, ready for the repository going public.

Not yet done: making the repository public (the updater reads releases anonymously), the first release, and
tools/install.ps1 (still the dev install to %LOCALAPPDATA%\Snip\app).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NU2B7qYmwKSf9hBMFJiH6A