Add automated broken link checker using Lychee

[danielle-teagarden]

Add automated broken link checker using Lychee

Description

This PR implements automated broken link checking as discussed in issue #1521. It uses Lychee, the tool recommended in the issue discussion.

Implementation Details

Files Added

1. .github/workflows/broken-links.yml - GitHub Action workflow that:

   • Runs monthly (1st of each month at 9 AM UTC)
   • Can be triggered manually via workflow_dispatch
   • Builds the site before checking links
   • Creates a single issue if broken links are found

2. .lycheeignore - Configuration file to reduce false positives by excluding:

   • Social media URLs (often block automated tools)
   • Authentication-required pages
   • Local development URLs
   • Known problematic domains

How It Works

1. Build First: The workflow builds the site to check actual output, not source files
2. Comprehensive Checking: Checks both internal and external links
3. Smart Retries: Retries failed requests up to 3 times with 20-second timeout
4. Single Issue: Creates one consolidated issue instead of multiple notifications
5. Appropriate Labels: Adds bug, help wanted, and content labels

Configuration Choices

Based on the discussion in #1521:

• ✅ Uses Lychee as suggested by @p2635
• ✅ Runs periodically (monthly) rather than on every commit
• ✅ Creates a single issue to avoid notification spam
• ✅ Includes common exclusions to reduce false positives

Testing

The workflow can be tested immediately after merging by:

1. Going to Actions tab
2. Selecting "Check for Broken Links" workflow
3. Clicking "Run workflow"

Questions for Review

1. Frequency: Currently set to monthly. Would you prefer a different schedule?
2. Assignees: Currently assigns @ericwbailey and @scottohara. Should this be changed?
3. Exclusions: Are there other domains that commonly give false positives?
4. Issue Title: Currently "Monthly Broken Links Report". Preference for different naming?

Related Issue

Resolves #1521

Additional Notes

• The action won't fail the workflow even if broken links are found (uses fail: false)
• The report is in markdown format for easy reading
• Future enhancements could include caching to speed up checks

[danielle-teagarden]

I've tested the workflow and discovered an issue - the build command should be npm run eleventy-build not npm run build (which doesn't exist in package.json). I've pushed a fix to correct this.

The workflow is now properly configured to:

1. Build the site with the correct command
2. Run Lychee on the generated _site directory
3. Create issues only when broken links are found
4. Run monthly on the 1st at 9 AM UTC

(Sorry for the early pull request; I turned my AI bot loose and it got a bit overzealous & excited to contribute; I'm excited too.)

[SaptakS]

Hi @danielle-teagarden , Thanks for working on this! I haven't taken a close look at it yet, but can you please update the PR to not include the PR-description files and the report.txt? I don't think we need to commit those to the repo.