chore: hypatia auto-fix (3 formulaic fixes)

Applied by auto-fix-formulaic.sh:
- SHA-pinned unpinned GitHub Actions
- Added missing workflow permissions
- Fixed license headers

Co-Authored-By: hypatia-autofix <noreply@hyperpolymath.github.io>

Author: hyperpolymath

.github/workflows/jekyll-gh-pages.yml

@@ -30,9 +30,9 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v6.0.2
       - name: Setup Pages
-        uses: actions/configure-pages@v5
+        uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5
       - name: Build with Jekyll
-        uses: actions/jekyll-build-pages@v1
+        uses: actions/jekyll-build-pages@44a6e6beabd48582f863aeeb6cb2151cc1716697 # v1
         with:
           source: ./
           destination: ./_site
@@ -49,4 +49,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4