feat: add deploy workflow

.github/workflows/deploy.yml

@@ -0,0 +1,39 @@
+name: Build & Deploy Site
+
+on:
+  push:
+    branches: [main]
+
+permissions:
+  contents: write
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+
+    defaults:
+      run:
+        working-directory: .
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+
+      - name: Install dependencies
+        working-directory: src/quartz
+        run: npm ci
+
+      - name: Build Quartz
+        working-directory: src/quartz
+        run: npx quartz build
+
+      - name: Deploy to GitHub Pages
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: src/public