Publish site via GitHub Pages with custom domain

Adds a GitHub Actions workflow that deploys site/flapjack-brothers on
every push to main, and a CNAME file for flapjack.p9o.uk. Pages is
configured on the repo to build via Actions, matching this workflow.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.github/workflows/pages.yml

@@ -0,0 +1,40 @@
+name: Deploy site to GitHub Pages
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - "site/flapjack-brothers/**"
+      - ".github/workflows/pages.yml"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v5
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: site/flapjack-brothers
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

site/flapjack-brothers/CNAME

@@ -0,0 +1 @@
+flapjack.p9o.uk