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/handles.test.ts

@@ -193,15 +193,18 @@ test("Node, ArcRotateCamera, and light handles update their shared rows", async
     color: [0.2, 0.4, 0.6],
     intensity: 7,
     range: 8,
+    radius: 2,
   });
   await light.ready;
   close(
     scene.array("pointLights").row(light.id),
-    [0.2, 0.4, 0.6, 7, 8, 1, 0, 0],
+    [0.2, 0.4, 0.6, 7, 8, 1, 2, 0],
   );
   light.intensity = 9;
   light.range = 10;
+  light.radius = 3;
   close(scene.array("pointLights").row(light.id).subarray(3, 5), [9, 10]);
+  assert.equal(scene.array("pointLights").row(light.id)[6], 3);
 });
 
 test("ArcRotateCamera pans one projected world pixel per pointer pixel", async () => {