What it does
Registers Shake It On as a macOS login item so it starts automatically every time you log in.
How it works
Uses `SMAppService.mainApp.register()` (the modern macOS 13+ API). The status syncs both ways — toggling in Settings registers/unregisters; flipping it in System Settings updates the toggle.
Where to find it
Settings → General → Launch Shake It On at login.
When to use it
If you find yourself manually launching Shake It On regularly. Combine with auto-disable for a clean 'on at login, off after 8 hours' default.