Function run_desktop 

pub fn run_desktop(
    title: &str,
    size: (u32, u32),
    root: impl FnMut(&mut Scheduler, &RenderContext) -> View + 'static,
) -> Result<()>

Desktop entry point. Mounts root on the repose-platform runner with the given window title/size. The root closure owns stepping (sim, rigs) and must call request_frame() for continuous frames; see the rozvp pilot runner for the reference wiring.