Fix CI: Add Node.js setup to build-node job

The build-node job was failing with 'node: not found' because it
runs scripts/validate.sh (which uses 'node -c' for syntax checking)
but didn't have the actions/setup-node@v4 step.

Added Node.js 22 setup before the validate step to match the pattern
used in other jobs.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/workflows/deploy.yml

@@ -251,6 +251,11 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      - name: Set up Node.js 22
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+
       - name: Validate JavaScript syntax
         run: sh scripts/validate.sh