Add GitHub Pages deploy workflow on gh-pages.

Enables Actions-based Pages publishing without changing main.

Co-authored-by: Ldsystem <Ldsystem@users.noreply.github.com>

Author: Ldsystem

.github/workflows/pages.yml

@@ -0,0 +1,35 @@
+name: Deploy GitHub Pages
+
+on:
+  push:
+    branches: [gh-pages]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Stage site files
+        run: |
+          mkdir -p _site
+          cp index.html _site/index.html
+          cp .nojekyll _site/.nojekyll
+      - uses: actions/configure-pages@v5
+      - uses: actions/upload-pages-artifact@v3
+        with:
+          path: _site
+      - id: deployment
+        uses: actions/deploy-pages@v4