Add FxNode render graph playground

Add persistent render graph loadouts, grouped node authoring, code-appending apply behavior, explicit playground lighting, and resilient worker startup.

Amp-Thread-ID: https://ampcode.com/threads/T-01a033d4-0e44-708e-af0e-6166283416ff
Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

addons/handles/test/scene-helpers.ts

@@ -13,8 +13,10 @@ export const triangle = {
   indices: [0, 1, 2],
 };
 
-export async function createScene() {
-  const scene = new Scene({} as HTMLCanvasElement);
+export async function createScene(
+  options: ConstructorParameters<typeof Scene>[1] = {},
+) {
+  const scene = new Scene({} as HTMLCanvasElement, options);
   await scene.ready;
   return scene;
 }