- Device Flow only works with 'TV and Limited Input devices' OAuth client type
- Desktop app type requires Authorization Code flow with localhost redirect
- New flow: start local TCP server on random port, open browser with auth URL,
catch redirect containing authorization code, exchange for tokens
- Uses webbrowser crate to auto-open the browser
- Self-contained: no separate HTTP server framework needed, uses std::net
- Popup shows auth URL and waits for browser authorization
- Support for refresh_token for long-lived access