ci: add link-check workflow (lychee)

[satyakwok]

Same pattern as the link-check workflow already shipped to awesome-sentrix, whitepaper, canonical-contracts, and dapp-starter. Lychee scans every markdown link on PR + push to main + weekly Monday 03:00 UTC cron. Non-blocking — mirrors the gitleaks workflow's policy.

Summary by CodeRabbit

• Chores
  • Added automated Markdown link validation to the CI/CD pipeline for improved repository quality.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 498f5436-8939-4565-80e5-5277321dfa17

📥 Commits

Reviewing files that changed from the base of the PR and between 33e48ab and 403b4b1.

📒 Files selected for processing (1)

• .github/workflows/link-check.yml

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📝 Walkthrough

Walkthrough

This PR adds a new GitHub Actions workflow file (.github/workflows/link-check.yml) that automatically validates hyperlinks in Markdown documentation. The workflow is triggered on pull requests, pushes to the main branch, and follows a weekly schedule. It uses the lychee link-checking action to scan all Markdown files, excludes email links, accepts specific HTTP status codes (200, 206, 403, 429), and runs with concurrency limits and non-blocking failure behavior to prevent CI blocking while still reporting issues.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'ci: add link-check workflow (lychee)' accurately and concisely describes the main change: adding a CI workflow for link checking using the lychee tool.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch ci/link-check

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