Function dispatch_slider_to_script 

pub fn dispatch_slider_to_script<H: ScriptHost + Resource<Mutability = Mutable>>(
    host: ResMut<'_, H>,
    events: MessageReader<'_, '_, SliderChanged>,
    ids: Query<'_, '_, &LumenId>,
    out: MessageWriter<'_, ScriptCommandEvent>,
)

Forward lumen_primitives::SliderChanged as on_slider(id, value) (f64), with per-id handler routing via on("slider", "<id>", "<fn>").