webgpu demo

implementations/main.cpp

@@ -18,7 +18,14 @@ int main() {
     // plus the rAF driver; even without subscribing to its events we need
     // it so StartSync() can keep the wasm module alive past main() (the
     // bridge stashes a raw pointer, so the storage has to outlive main).
-    static Window window(0, 0, "Catcrafts");
+    // The dimensions are a hint only — the JS bridge sizes the render
+    // surface to the canvas (full viewport, or the mount element).
+    static Window window(1280, 720, "Catcrafts");
+
+    // Build the ray-tracing pipeline + scene now (runs StartInit/FinishInit).
+    // The render canvas starts hidden; the demo only traces once a route
+    // mounts it into #webgpu-demo (see Catcrafts:Demo).
+    SetupDemo(window);
 
     InitializePage();
 
@@ -34,6 +41,7 @@ int main() {
 
     RenderRoot(Router::GetPath());
 
+    window.Render();
     window.StartUpdate();
     window.StartSync();
     return 0;