workflow: optimize external link checks

[qiancai]

What is changed, added or deleted? (Required)

This PR optimizes the lychee link-check workflows as follows:

• Updates the weekly full-repository link check to focus on external URLs and exclude file:// internal links.
• Adds shared scripts to extract site href URLs and changed Markdown lines with link candidates.
• Converts non-HTTP href values such as href="/tidbcloud/tidb-cloud-quickstart" into URLs based on DOCS_SITE_BASE_URL before checking them.
• Changes the PR link check to scan only added/modified lines that contain link candidates, instead of every changed Markdown file.
• Keeps lychee cache for the weekly full scan, but caches only successful 2xx responses so failed links are rechecked in later runs.
• Adds ignore rules for bot-unfriendly or auth-gated external sites reported in recent link-check issues.

Benefits:

• Reduces false positives from docs site route links that lychee previously treated as missing local files.
• Makes PR checks much faster for broad edits that do not add or modify links, such as deleting aliases across many files.
• Keeps full scheduled scans reasonably fast while still rechecking previously failed links.
• Centralizes the href extraction logic so the workflow can be reused more easily in the Chinese docs repository by changing DOCS_SITE_BASE_URL.

Which TiDB version(s) do your changes apply to? (Required)

• master (the latest development version)
• v9.0 (TiDB 9.0 versions)
• v8.5 (TiDB 8.5 versions)
• v8.1 (TiDB 8.1 versions)
• v7.5 (TiDB 7.5 versions)
• v7.1 (TiDB 7.1 versions)
• v6.5 (TiDB 6.5 versions)
• v6.1 (TiDB 6.1 versions)

What is the related PR or file link(s)?

• This PR is translated from:
• Other reference link(s): Broken Link Detected #22892

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch

[ti-chi-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[gemini-code-assist]

Code Review

This pull request introduces two Perl scripts, extract-changed-markdown-lines.pl and extract-site-hrefs.pl, designed to automate the extraction and validation of links within documentation. It also updates the .lycheeignore file to include several new external domains and corrects a regex pattern for TiDB operator versions. Feedback on the extract-site-hrefs.pl script identifies critical issues including a global record separator conflict that affects file reading, incorrect resolution of relative links in subdirectories, and the need to ignore the file: protocol to prevent invalid URL generation.

[Oreoxmt]

/cc @Oreoxmt

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-05-15 06:41:51.143239874 +0000 UTC m=+420679.676019183: ☑️ agreed by Oreoxmt.

[qiancai]

/approve

[ti-chi-bot]

@qiancai: You cannot manually add or delete the cherry pick approval state labels, only I and the tursted members have permission to do so. You can approve it in internal platform.

Details

In response to removing label named approved.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[qiancai]

/approve

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: qiancai

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [qiancai]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.5: #22896.
But this PR has conflicts, please resolve them!