Refactor GitHub Actions workflow to improve readability and add SPA routing for 404 handling

Author: vijaisuria

.github/workflows/deploy.yml

@@ -22,22 +22,25 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      
+
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
           node-version: "20"
           cache: "npm"
-      
+
       - name: Setup Pages
         uses: actions/configure-pages@v4
-      
+
       - name: Install dependencies
         run: npm ci
-      
+
       - name: Build
         run: npm run build
-      
+
+      - name: Copy index.html to 404.html for SPA routing
+        run: cp dist/index.html dist/404.html
+
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v3
         with: