Add a windows11 target that downloads the Windows 11 ISO with headless Chromium

Move the Node.js script and its dependencies into nodejs/ and let
download-images.sh call it for the image architecture.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

nodejs/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "win-iso",
+  "version": "1.0.0",
+  "description": "",
+  "main": "get-windows-iso-url.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "type": "commonjs",
+  "dependencies": {
+    "playwright-core": "^1.64.1"
+  }
+}