MixDesk X 1.42.013

Windows: the "System audio" input option now works properly — one click routes your Windows default output through the free VB-Cable and picks it up as a channel source (same pattern as the macOS driver route). Platform-specific setup hints (Windows now points to vb-audio.com/Cable instead of the macOS driver), and a warning before selecting a loopback source that would feed back into its own output bus.