Replace deprecated URL checker action with direct invocation (OWASP#3332)

* Replace deprecated URL checker action with maintained fork

gaurav-nelson/github-action-markdown-link-check is explicitly deprecated
and points to tcort/github-action-markdown-link-check as its successor.
The new action is actively maintained by the upstream markdown-link-check
package author and uses the same config file format.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Test: add intentionally broken link to verify URL checker

This broken link should trigger a failure in the URL checker workflow,
confirming the new action correctly detects dead links. This commit
should be reverted before merging.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Debug: add verbose output and direct markdown-link-check test

- Add a step that runs markdown-link-check directly (outside Docker)
  to see raw output and verify it detects the broken link
- Disable quiet mode and enable verbose mode on the action step
- This is a temporary debug commit to be reverted

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Replace Docker-based action with direct markdown-link-check invocation

The tcort/github-action-markdown-link-check Docker action has a known
bug (OWASP#553) where markdown-link-check silently fails inside the container,
reporting all links as good without checking anything.

This replaces the action with direct npm installation and invocation of
markdown-link-check, which works correctly on the runner. Also fixes the
PR modified-files detection by using fetch-depth: 0 for proper git diff.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Remove intentionally broken test link

The URL checker has been verified to correctly detect broken links.
Removing the test link added for debugging.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: tghosth

.github/workflows/url-checker.yml

@@ -17,23 +17,39 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4.2.2
+        with:
+          fetch-depth: 0
+
+      - name: Install markdown-link-check
+        run: npm i -g markdown-link-check@3.14.2
 
-      - name: Set options
-        id: options
+      - name: Determine files to check
+        id: files
         run: |
           if [[ "${{ github.event_name }}" == "pull_request" ]]; then
-            echo "check-modified-files-only=yes" >> $GITHUB_OUTPUT
-            echo "use-verbose-mode=yes" >> $GITHUB_OUTPUT
+            git diff --name-only --diff-filter=AM origin/${{ github.base_ref }} -- 5.0/ | grep '\.md$' > /tmp/files_to_check.txt || true
+            echo "mode=modified" >> $GITHUB_OUTPUT
           else
-            echo "check-modified-files-only=no" >> $GITHUB_OUTPUT
-            echo "use-verbose-mode=no" >> $GITHUB_OUTPUT
+            find 5.0 -name '*.md' -not -path './node_modules/*' > /tmp/files_to_check.txt
+            echo "mode=all" >> $GITHUB_OUTPUT
           fi
+          echo "Checking files (mode: $(cat $GITHUB_OUTPUT | grep mode | cut -d= -f2)):"
+          cat /tmp/files_to_check.txt
 
       - name: Check URLs
-        uses: gaurav-nelson/github-action-markdown-link-check@v1
-        with:
-          check-modified-files-only: ${{ steps.options.outputs.check-modified-files-only }}
-          config-file: .github/workflows/config/url-checker-config.json
-          folder-path: '5.0'
-          use-quiet-mode: yes
-          use-verbose-mode: ${{ steps.options.outputs.use-verbose-mode }}
+        run: |
+          ERROR_FOUND=0
+          while IFS= read -r file; do
+            if [ -n "$file" ]; then
+              markdown-link-check "$file" --config .github/workflows/config/url-checker-config.json -q || ERROR_FOUND=1
+            fi
+          done < /tmp/files_to_check.txt
+
+          if [ "$ERROR_FOUND" -eq 1 ]; then
+            echo ""
+            echo "ERROR: Dead links were found!"
+            exit 1
+          else
+            echo ""
+            echo "All links are good!"
+          fi