Add a link checker (#1776)

Author: dallasread

.github/workflows/links.yml

@@ -0,0 +1,42 @@
+name: Links
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check-links:
+    name: Check Links
+    runs-on: ubuntu-latest
+    env:
+      BUNDLE_JOBS: 3
+    steps:
+      - name: Clone repository
+        uses: actions/checkout@v6
+
+      - name: Install Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          bundler-cache: true
+
+      - name: Install Node
+        uses: actions/setup-node@v6
+        with:
+          node-version-file: '.tool-versions'
+          cache: yarn
+
+      - name: Install JS Deps
+        run: yarn install --frozen-lockfile
+
+      - name: Compile site
+        run: bundle exec rake compile
+
+      - name: Check links
+        uses: lycheeverse/lychee-action@a8c4c7cb88f0c7386610c35eb25108e448569cb0 # v2
+        with:
+          args: '--root-dir ${{ github.workspace }}/output output/**/*.html'
+          fail: true

.lychee.toml

@@ -0,0 +1,11 @@
+# Remap absolute support site URLs to relative paths for local file checking.
+# This lets lychee verify internal links against the compiled output
+# instead of hitting the live site.
+remap = [
+    "https://support\\.dnsimple\\.com(.*) $1"
+]
+
+exclude_mail = true
+max_concurrency = 5
+max_retries = 3
+timeout = 30