refactor(渲染): 将视图投影矩阵设置移至Application层

重构渲染流程，将视图投影矩阵的设置从Scene移动到Application层，通过CameraService统一管理。同时更新示例代码以适配此变更，确保视口配置正确应用。

Extra2D/src/app/application.cpp

@@ -334,6 +334,8 @@ void Application::render() {
         renderer->setViewport(
             static_cast<int>(vp.origin.x), static_cast<int>(vp.origin.y),
             static_cast<int>(vp.size.width), static_cast<int>(vp.size.height));
+        
+        renderer->setViewProjection(cameraService->getViewProjectionMatrix());
     } else {
         renderer->setViewport(0, 0, window_->width(), window_->height());
     }

Extra2D/src/scene/scene.cpp

@@ -62,20 +62,15 @@ void Scene::renderScene(RenderBackend &renderer) {
  * @brief 渲染场景内容
  * @param renderer 渲染后端引用
  *
- * 批量更新节点变换，设置活动相机的视图投影矩阵，开始精灵批处理并渲染
+ * 批量更新节点变换，开始精灵批处理并渲染
+ * 注意：视图投影矩阵由 Application 通过 CameraService 设置
  */
 void Scene::renderContent(RenderBackend &renderer) {
   if (!isVisible())
     return;
 
-  // 在渲染前批量更新所有节点的世界变换
   batchTransforms();
 
-  Camera *activeCam = getActiveCamera();
-  if (activeCam) {
-    renderer.setViewProjection(activeCam->getViewProjectionMatrix());
-  }
-
   renderer.beginSpriteBatch();
   render(renderer);
   renderer.endSpriteBatch();

examples/basic/main.cpp

@@ -144,6 +144,17 @@ int main(int argc, char *argv[]) {
   scene->setViewportSize(static_cast<float>(app.window().width()),
                          static_cast<float>(app.window().height()));
 
+  auto cameraService = app.camera();
+  if (cameraService) {
+    ViewportConfig vpConfig;
+    vpConfig.logicWidth = static_cast<float>(app.window().width());
+    vpConfig.logicHeight = static_cast<float>(app.window().height());
+    vpConfig.mode = ViewportMode::AspectRatio;
+    cameraService->setViewportConfig(vpConfig);
+    cameraService->updateViewport(app.window().width(), app.window().height());
+    cameraService->applyViewportAdapter();
+  }
+
   createSceneGraph(scene.get());
 
   app.enterScene(scene);