chore(ci): Migrate Pages to custom workflow with Node 24 actions

Replaces the auto pages-build-deployment (which still uses Node-20 actions/checkout@v4 and actions/upload-artifact@v4) with a custom workflow using configure-pages@v6, jekyll-build-pages@v1.0.13, upload-pages-artifact@v5, deploy-pages@v5.

Triggered by release publication so the changelog Liquid template (which reads site.github.releases) only rebuilds when a release actually exists. workflow_dispatch is kept for manual rebuilds when debugging Pages content.

.github/workflows/pages.yml

@@ -0,0 +1,49 @@
+name: Deploy GitHub Pages
+
+on:
+  release:
+    types: [ published ]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: false
+
+jobs:
+  build:
+    name: Build Jekyll site
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd #v6.0.2
+        with:
+          persist-credentials: false
+
+      - name: Configure Pages
+        uses: actions/configure-pages@45bfe0192ca1faeb007ade9deae92b16b8254a0d #v6.0.0
+
+      - name: Build with Jekyll
+        uses: actions/jekyll-build-pages@44a6e6beabd48582f863aeeb6cb2151cc1716697 #v1.0.13
+        with:
+          source: ./
+          destination: ./_site
+
+      - name: Upload Pages artifact
+        uses: actions/upload-pages-artifact@fc324d3547104276b827a68afc52ff2a11cc49c9 #v5.0.0
+
+  deploy:
+    name: Deploy to GitHub Pages
+    needs: build
+    runs-on: ubuntu-22.04
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@cd2ce8fcbc39b97be8ca5fce6e763baed58fa128 #v5.0.0