refactor: build the app with Application::create

Application::new(qh, sender) took the session's Wayland queue handle,
which no client ever used, and calloop's sender; cce-ui is retiring it
for create(sender: AppSender<_>), which names no window system. The
body is unchanged: an app that keeps calloop's sender converts the
AppSender into it on the first line, and the now-unused QueueHandle and
EngineState imports go.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

 src/main.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index 7e5a096..710d03e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -216,7 +216,9 @@ fn emit_control_carve(pc: &mut cce_ui::scene::paint::PaintCtx, carve: ControlCar
 impl cce_ui::engine::Application for SystemInterface {
     type Message = AppAction;
 
-    fn new(_qh: &wayland_client::QueueHandle<cce_ui::engine::EngineState<Self>>, sender: calloop::channel::Sender<Self::Message>) -> Self {
+    fn create(sender: cce_ui::engine::AppSender<Self::Message>) -> Self {
+        // The app keeps calloop's sender; `AppSender` converts into it.
+        let sender: calloop::channel::Sender<Self::Message> = sender.into();
         cce_ui::scale::set_scale_factor(1.0);
         let app = AppState::default();