Fix high-signal widget and Wayland warnings

Avoid recursive operation traversal, execute visible list updates instead of leaving a lazy iterator unused, remove unreachable cfg-gated surface creation code, and handle subsurface buffer attachment failures.

winit/src/platform_specific/mod.rs

@@ -153,9 +153,12 @@ impl PlatformSpecific {
     ) -> Option<Box<dyn HasWindowHandle + Send + Sync + 'static>> {
         #[cfg(all(feature = "cctk", target_os = "linux"))]
         {
-            return self.wayland.create_surface();
+            self.wayland.create_surface()
+        }
+        #[cfg(not(all(feature = "cctk", target_os = "linux")))]
+        {
+            None
         }
-        None
     }
 
     pub(crate) fn update_surface_shm(