build(deploy): Jekyll 4 + minima 2.5 via GitHub Actions Pages

.github/workflows/pages.yml

@@ -0,0 +1,50 @@
+name: Build and deploy Jekyll to Pages
+
+on:
+  push:
+    branches: [master]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: "3.4"
+          bundler-cache: true
+      - name: Configure Pages
+        uses: actions/configure-pages@v5
+      - name: Build site
+        env:
+          JEKYLL_ENV: production
+        run: bundle exec jekyll build --trace --strict-front-matter --future
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: _site
+
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

.github/workflows/test.yml

@@ -30,7 +30,7 @@ jobs:
       - run: bundle exec jekyll build --strict-front-matter --future
       # Internal links, images, and alt text only — external URLs are
       # left out to keep PR checks deterministic (no network flakiness).
-      # Installed outside the Gemfile on purpose: production (GitHub
-      # Pages) must keep the exact github-pages gem set.
+      # Installed outside the Gemfile on purpose to keep the deployed
+      # gem set minimal (check-only dependency, never shipped to Pages).
       - run: gem install html-proofer --no-document
       - run: htmlproofer ./_site --disable-external --allow-hash-href

.ruby-version

@@ -0,0 +1 @@
+3.4

Gemfile

@@ -1,17 +1,19 @@
 source "https://rubygems.org"
 
-# GitHub Pages builds the site with Jekyll 3.9.x. Pinning to the github-pages
-# gem keeps the local build environment identical to the one used for
-# deployment, so there are no surprises when the site goes live.
-gem "github-pages", group: :jekyll_plugins
+# Deployed with a custom GitHub Actions workflow (.github/workflows/pages.yml),
+# not the legacy branch-based Pages build. This allows Jekyll 4 + current
+# plugins instead of the pinned github-pages gem set.
+gem "jekyll", "~> 4.4.1"
 
-# Default theme for Jekyll sites. You may change this to anything you like.
-gem "minima"
+# Current theme release (2.5.2 is latest; see _config.yml re: `skin`).
+gem "minima", "~> 2.5.2"
 
-# The github-pages stack relies on these default gems, which are no longer
-# bundled with Ruby >= 3.4.
-gem "logger"
-gem "csv"
+group :jekyll_plugins do
+  gem "jekyll-feed", "~> 0.17"
+  gem "jekyll-sitemap", "~> 1.4"
+  gem "jekyll-seo-tag", "~> 2.8"
+  gem "jekyll-redirect-from", "~> 0.16"
+end
 
 # Ruby >= 3.0 no longer ships WEBrick, which Jekyll needs for `serve`.
-gem "webrick", "~> 1.7"
+gem "webrick", "~> 1.9"