Publish the documentation on GitHub Pages

.gitattributes

@@ -13,3 +13,4 @@
 /test-git-versions.php export-ignore
 /tests export-ignore
 /tools export-ignore
+/zensical.toml export-ignore

.github/dependabot.yml

@@ -11,3 +11,11 @@ updates:
       - /tools/phpstan
     schedule:
       interval: monthly
+
+  - package-ecosystem: pip
+    directory: /tools/zensical
+    schedule:
+      interval: monthly
+    groups:
+      zensical:
+        patterns: ['*']

.github/workflows/docs.yml

@@ -0,0 +1,76 @@
+name: Documentation
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    paths:
+      - .github/workflows/docs.yml
+      - CHANGELOG.md
+      - README.md
+      - UPGRADE-2.0.md
+      - doc/**
+      - tools/zensical/**
+      - zensical.toml
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  # Let a deployment finish: the next one waits.
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+jobs:
+  build:
+    name: Build the Documentation
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v7
+        with:
+          # The site is published: keep the token out of the workspace.
+          persist-credentials: false
+
+      - name: Setup Python
+        uses: actions/setup-python@v7
+        with:
+          python-version: '3.14'
+          cache: pip
+          cache-dependency-path: tools/zensical/requirements.txt
+
+      - name: Install Zensical
+        run: pip install -r tools/zensical/requirements.txt
+
+      - name: Write the pages
+        run: python tools/zensical/pages.py
+
+      # Strict, as configured in zensical.toml: a broken link or anchor fails.
+      - name: Build the site
+        run: zensical build --clean
+
+      - name: Upload the site
+        if: github.ref == 'refs/heads/main'
+        uses: actions/upload-pages-artifact@v5
+        with:
+          path: site
+
+  deploy:
+    name: Deploy to GitHub Pages
+    if: github.ref == 'refs/heads/main'
+    needs: build
+    runs-on: ubuntu-24.04
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Setup Pages
+        uses: actions/configure-pages@v6
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v5

.gitignore

@@ -3,6 +3,7 @@
 /.phpunit.cache
 /composer.lock
 /phpunit.xml
+/site/
 /var/
 /vendor
 /git-builds/