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/fxnode_rg/test/run.mjs

@@ -0,0 +1,37 @@
+import { mkdtemp, readdir, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { basename, join } from "node:path";
+import { fileURLToPath } from "node:url";
+import { spawnSync } from "node:child_process";
+import { build } from "esbuild";
+
+const directory = fileURLToPath(new URL(".", import.meta.url));
+const output = await mkdtemp(join(tmpdir(), "yawn-fxnode-rg-tests-"));
+
+try {
+  const entries = (await readdir(directory))
+    .filter((name) => name.endsWith(".test.ts"))
+    .sort()
+    .map((name) => join(directory, name));
+  await build({
+    entryPoints: entries,
+    outdir: output,
+    entryNames: "[name]",
+    outExtension: { ".js": ".mjs" },
+    bundle: true,
+    format: "esm",
+    platform: "node",
+    target: "node20",
+    sourcemap: "inline",
+  });
+  const tests = entries.map((entry) =>
+    join(output, `${basename(entry, ".ts")}.mjs`),
+  );
+  const result = spawnSync(process.execPath, ["--test", ...tests], {
+    stdio: "inherit",
+  });
+  if (result.error) throw result.error;
+  process.exitCode = result.status ?? 1;
+} finally {
+  await rm(output, { force: true, recursive: true });
+}