Set minimum screen brightness level to 1, not 0

systemd/src/main.rs

@@ -92,5 +92,8 @@ async fn do_bscreensaver_command(command: BCommand) -> anyhow::Result<()> {
 
 async fn register_sleep_lock<'a>(manager_proxy: &ManagerProxy<'a>) -> anyhow::Result<zbus::zvariant::OwnedFd> {
     debug!("Registering sleep lock");
+    // ManagerProxy uses RawFd for the return value, which rust's type system thinks is an i32,
+    // which means the generated proxy uses the wrong dbus type signature.  So instead, use a raw
+    // Proxy instance and do it all ourselves.
     Ok(manager_proxy.inhibit(InhibitType::Sleep, "bscreensaver", "blank before sleep", "delay").await?)
 }