Restore a view's visual style; no background in 2D wireframe

Restoring a named view gives the model viewport the view's visual style
(the closest render mode), and a 2D wireframe viewport shows no
background, as in the reference.

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

src/scene/camera_ops.rs

@@ -219,6 +219,13 @@ impl Scene {
         if self.current_layout == "Model" {
             let background = copy_background(&mut self.document, view.background_handle);
             self.set_active_background(background);
+            if view.visual_style_handle.is_valid() {
+                if let Some(handle) = self.active_tile_vport_handle() {
+                    if let Some(value) = self.document.vports.iter_mut().find(|v| v.handle == handle) {
+                        value.visual_style_handle = view.visual_style_handle;
+                    }
+                }
+            }
         }
         let cam = &mut *self.camera.borrow_mut();
         // The stored direction points from the target toward the eye.

src/scene/view/render.rs

@@ -2571,11 +2571,15 @@ impl Scene {
         } else if self.current_layout == "Model" {
             let index = viewport.tile_idx.unwrap_or(0);
             if let Some(value) = self.model_tile_vport(index) {
+                // A 2D wireframe view shows no background, as in the reference.
+                let flat = self.model_tiles.borrow().get(index).is_some_and(|tile| {
+                    tile.render_mode == codec::entities::ViewportRenderMode::Wireframe2D
+                });
                 return build(
                     value.visual_style_handle,
                     value.brightness,
                     value.contrast,
-                    value.background_handle,
+                    if flat { Handle::NULL } else { value.background_handle },
                 );
             }
         }