Add build step to GitHub Actions workflow

Author: tellmeY18

.github/workflows/deploy.yml

@@ -36,6 +36,7 @@ jobs:
         run: npm ci  # Use 'ci' instead of 'install' for reproducible builds
 
       - name: Build
+        run: npm run build
 
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v3