custom markdown list check action

[YanxuanLiu]

Create custom markdown list check action, since

1. https://github.com/gaurav-nelson/github-action-markdown-link-check has been deprecated. Changed to https://github.com/tcort/github-action-markdown-link-check
2. Output error items at the end of log for better readability.

Test runs:

1. found error links
2. all links valid

[Copilot]

Pull Request Overview

Creates a custom GitHub Action for checking markdown links to replace the deprecated gaurav-nelson action with tcort/github-action-markdown-link-check, while adding improved error output formatting that summarizes error items at the end of logs for better readability.

• Replaces deprecated markdown link check action with tcort/github-action-markdown-link-check
• Adds custom output processing to collect and display error summaries at the end
• Includes GitHub workflow configuration for running the action on pull requests

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
markdown-link-check/action.yml	Custom composite action that wraps tcort/github-action-markdown-link-check with enhanced error reporting
.github/workflows/markdown-link-check.yml	Workflow configuration to run the markdown link check on pull requests

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