Slint's interpreter can be much slower than using precompiled UI with slint-build

It might be useful to provide a modular platform, for example a LayerShell, that can be used like this:

slint::include_modules!();
fn main() {
    let mut platform = LayerShell::new().unwrap();
    platform.set_anchor(Anchor::Top);
    platform.set_exclusive_zone(-1);

    slint::platform::set_platform(platform);

    let ui = MainWindow::new().unwrap();
    ui.run().unwrap();
}

This way, developers could create "Slint-style" applications for shells directly, without relying on another framework on top.

I think shells could be more modular, like KDE or COSMIC. Monolithic shells, like GNOME Shell, are nice because users “cannot break them,” but they limit customization. A modular approach could give both stability and flexibility.