Add build step to GitHub Actions workflow

.github/workflows/docker-publish.yml

@@ -23,6 +23,17 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
+      - name: Setup Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run production build
+        run: npm run build
+
       - name: Log in to GHCR
         uses: docker/login-action@v3
         with: