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>

README.md

@@ -30,6 +30,26 @@ arm64 hosts) and `.iso` in that order (`*Win*11*x64*.iso` or
 version-sorted name is used. Check which file was picked with
 `./download-images.sh --print-path windows11 --iso`.
 
+To get a fresh temporary URL, `nodejs/get-windows-iso-url.js` drives Microsoft's
+download page with headless Chromium (needs Node.js and an installed
+Chromium, for example from Playwright):
+
+```bash
+cd nodejs
+npm ci                                            # once, installs playwright-core
+node get-windows-iso-url.js                       # print the URL for the host architecture
+node get-windows-iso-url.js --arch arm64          # choose the architecture explicitly
+```
+
+The script only prints the URL. `./download-images.sh windows11` downloads that
+URL into `install-iso/` like the other images (aria2c, resumable) for the image
+architecture (`VM_IMAGE_ARCH=arm64` for arm64), and skips it when a matching ISO
+is already there. The `all` target does not include it.
+
+The URL expires after about 24 hours and may be bound to the IP that requested
+it, so download from the machine that ran the script. Run it with `--help` for
+the language and path options.
+
 ## Query image paths
 
 The path interface prints one absolute path without downloading anything: