Add Hex file download tool information (#7009)

* Add Hex file download tool information

Added section about Hex file download tool for WebUSB.

* Rephrase instructions for using Hex Download Tool

* Clarify hex file download tool usage with WebUSB

* Fix buildpush CI failure: update Node.js to 22.x for npm@latest compatibility

---------

Co-authored-by: Galen Nickel <gnickel@aquent.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

Author: 3 people

.github/workflows/pxt-buildpush.yml

@@ -42,7 +42,7 @@ jobs:
       - name: Use Node.js
         uses: actions/setup-node@main
         with:
-          node-version: 20.x
+          node-version: 22.x
 
       - name: Update npm
         run: npm install -g npm@11
@@ -76,7 +76,7 @@ jobs:
       - name: Use Node.js
         uses: actions/setup-node@main
         with:
-          node-version: 20.x
+          node-version: 22.x
 
       - name: Update npm
         run: npm install -g npm@11

docs/device/usb/webusb.md

@@ -88,3 +88,7 @@ If you don't want to use WebUSB any longer, you will need to unpair your device
 3. Reload the MakeCode editor page.
 
 ![Unpairing from the browser](/static/download/browser-unpair-image.gif)
+
+## Hex file download tool
+
+Use The [Hex Download Tool](https://microbit.org/tools/webusb-hex-download-tool) from the Micro:bit Foundation to download hex files to one or more micro:bits directly with WebUSB (without going through MakeCode).