Add VitePress docs site with MoonBit highlighting

.github/workflows/docs.yml

@@ -0,0 +1,59 @@
+name: Docs
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: docs-pages
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build docs site
+        run: npm run docs:build
+
+      - name: Configure Pages
+        if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+        uses: actions/configure-pages@v5
+
+      - name: Upload Pages artifact
+        if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: docs/.vitepress/dist
+
+  deploy:
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4