fix(pages): supply the Pages workflow the repository was configured for but never had

.github/workflows/casket-pages.yml

@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: MPL-2.0
+#
+# GitHub Pages deployment.
+#
+# This repository has Pages configured with build_type "workflow", but carried
+# no Pages workflow — so the build never ran and the site was never published.
+# https://hyperpolymath.github.io/nesy-solver/ returned 404 for the site root
+# and for /.well-known/security.txt alike.
+#
+# WHY THIS STAGES A SUBSET RATHER THAN PUBLISHING THE REPOSITORY ROOT
+#
+# index.html references /public/styles.css and /public/app.js, and the site
+# needs .well-known/ at its root. Those three things, plus the entry page, are
+# what is staged. Publishing the repository root instead would serve 45 root
+# files — AUDIT.adoc, Containerfile, server.js, wrangler.toml and the rest —
+# none of which is site content.
+name: GitHub Pages
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
+
+      - name: Stage the site
+        run: |
+          set -euo pipefail
+          mkdir -p _site
+          cp index.html _site/index.html
+          [ -d public ] && cp -r public _site/public
+          # .well-known/ must sit at the ORIGIN ROOT to be discoverable
+          # (RFC 8615). nesy-solver.dev does not currently resolve, so nothing
+          # serves it today; this keeps it correct at whatever origin does.
+          [ -d .well-known ] && cp -r .well-known _site/.well-known
+          echo "staged:"
+          find _site -type f | sed 's/^/  /'
+
+      - name: Setup Pages
+        uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3
+        with:
+          path: '_site'
+
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4