In-app auto-update from GitHub Releases (Velopack)

[dvdstelt]

Summary

Adds opt-in in-app auto-update. The app checks GitHub Releases on startup and every six hours; when a newer stable release is found it shows a bold "Restart to update to vX.Y.Z" item at the top of the tray menu plus a balloon. Nothing installs until you click it, then it downloads and restarts into the new version.

Only the installed (Setup.exe) build is Velopack-managed, so the portable exe and dotnet run quietly no-op.

Where it updates from

Straight from this repo's GitHub Releases — no separate update server. GithubSource lists releases, picks the newest non-prerelease, reads its releases.win.json feed + .nupkg assets, and compares against the running version.

Changes

• Update/UpdateService.cs (new) — wraps Velopack UpdateManager, IsInstalled-guarded.
• AppController.cs — startup + 6-hour check; reveals the tray prompt; failed checks are swallowed quietly.
• TrayIcon.cs — the hidden-until-found update item + info balloon.
• .github/workflows/release.yml — publish the Velopack feed (.nupkg + releases.*.json) as release assets, staged after the SignPath step so signing stays scoped to the exes. This is required — without the feed attached, the updater has nothing to read.
• README.md — document the behavior.

Testing

• dotnet build clean, 34/34 tests pass, app launches without regression.
• End-to-end update can only be exercised from an installed build against a newer published release (dev runs no-op by design).

Notes

• Always-on background checks with a prompt; a settings toggle to disable them can be added later if wanted.
• Signing: ships unsigned for now. If code signing is adopted later, move it to pack-time so the exe inside the .nupkg is signed too.