ci(demo): migrate deployment to GitHub Actions

Add GitHub Actions workflow to deploy the demo on v* tag pushes.
The workflow validates that the tag version matches both package.json
files before building and deploying to GitHub Pages.

Remove the demo:push script and simplify demo:publish to only handle
cleaning and building, as deployment is now handled by CI.

Author: orrisroot

.github/workflows/demo-deploy.yml

@@ -0,0 +1,54 @@
+name: Deploy Demo
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: write
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Validate versions match
+        run: |
+          TAG_VERSION="${GITHUB_REF#refs/tags/v}"
+          ROOT_VERSION=$(node -p "require('./package.json').version")
+          DEMO_VERSION=$(node -p "require('./demo/package.json').version")
+          if [ "$TAG_VERSION" != "$ROOT_VERSION" ]; then
+            echo "::error::Tag version ($TAG_VERSION) does not match root package.json ($ROOT_VERSION)"
+            exit 1
+          fi
+          if [ "$TAG_VERSION" != "$DEMO_VERSION" ]; then
+            echo "::error::Tag version ($TAG_VERSION) does not match demo package.json ($DEMO_VERSION)"
+            exit 1
+          fi
+          echo "All versions match: $TAG_VERSION"
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 24
+          cache: npm
+
+      - name: Install root dependencies
+        run: npm ci
+
+      - name: Install demo dependencies
+        working-directory: demo
+        run: npm ci
+
+      - name: Build demo
+        run: npm run demo:build
+
+      - name: Deploy to GitHub Pages
+        uses: peaceiris/actions-gh-pages@v4
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./demo/dist
+          force_orphan: true

package.json

@@ -41,8 +41,7 @@
     "demo:clean": "rimraf demo/dist",
     "demo:dev": "cd demo && npm run dev",
     "demo:build": "cd demo && npm run build",
-    "demo:push": "cd demo/dist && git init && git commit --allow-empty -m 'update demo' && git checkout -b gh-pages && git add . && git commit -am 'update demo' && git push git@github.com:orrisroot/react-html-parser gh-pages --force",
-    "demo:publish": "npm run demo:clean && npm run demo:build && npm run demo:push"
+    "demo:publish": "npm run demo:clean && npm run demo:build"
   },
   "repository": {
     "type": "git",