v0.3.0 — System tray, auto-update & window fix

What's new

• Background running: closing the window now minimizes to system tray instead of quitting. Right-click the tray icon to reopen or quit.
• Auto-update: the app will automatically download new releases in the background and prompt you to restart — no more manual uninstall/reinstall.
• Fix: app window was not appearing on launch (showed in Task Manager but no UI).