feat: Add GitHub Actions workflow for deploying to GitHub Pages and include CNAME file

.github/workflows/gh-pages.yml

@@ -0,0 +1,37 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build project
+        run: npm run build
+
+      - name: Copy CNAME (if exists)
+        run: |
+          if [ -f public/CNAME ]; then
+            cp public/CNAME public/build/CNAME
+          fi
+
+      - name: Deploy to GitHub Pages
+        uses: peaceiris/actions-gh-pages@v4
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./public/build
+          publish_branch: gh-pages