fix: configure lychee link checker for Astro base path (#121)

Add lychee.toml with remap rule to strip /tutorial-git/ prefix,
re-enable link checking in both build and deploy workflows.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: braboj

.github/workflows/build.yml

@@ -30,9 +30,8 @@ jobs:
         working-directory: astro-site
         run: npm run build
 
-      # TODO: Fix lychee configuration for Astro's base path and fragment links (#121)
-      # - name: Check links
-      #   uses: lycheeverse/lychee-action@v2
-      #   with:
-      #     args: --base ${{ github.workspace }}/astro-site/dist --root-dir ${{ github.workspace }}/astro-site/dist astro-site/dist
-      #     fail: true
+      - name: Check links
+        uses: lycheeverse/lychee-action@v2
+        with:
+          args: --base astro-site/dist --config lychee.toml 'astro-site/dist/**/*.html'
+          fail: true

.github/workflows/deploy.yml

@@ -39,12 +39,11 @@ jobs:
         working-directory: astro-site
         run: npm run build
 
-      # TODO: Fix lychee configuration for Astro's base path and fragment links (#121)
-      # - name: Check links
-      #   uses: lycheeverse/lychee-action@v2
-      #   with:
-      #     args: --base ${{ github.workspace }}/astro-site/dist --root-dir ${{ github.workspace }}/astro-site/dist astro-site/dist
-      #     fail: true
+      - name: Check links
+        uses: lycheeverse/lychee-action@v2
+        with:
+          args: --base astro-site/dist --config lychee.toml 'astro-site/dist/**/*.html'
+          fail: true
 
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v3

lychee.toml

@@ -0,0 +1,23 @@
+# Lychee link checker configuration
+# Runs against the Astro build output in astro-site/dist/
+
+# Remap the /tutorial-git/ base path to the dist root so that
+# root-relative links like /tutorial-git/introduction/ resolve
+# to dist/introduction/index.html
+remap = ["/tutorial-git/(.*) file:///$1"]
+
+# Skip external links in CI to avoid flaky failures from transient
+# network issues. Run with --include-mail to check mailto: links.
+exclude_path = []
+
+# Exclude external URLs to keep CI fast and deterministic
+exclude = [
+  "^https://",
+  "^http://",
+]
+
+# Accept 200 and 204
+accept = [200, 204]
+
+# No caching needed in CI
+no_progress = true