Fix linkchecker: add config file and exclude live branch

[Dickson-Mwendia]

• Add .lychee.toml so lychee doesn't mistakenly parse package.json as config
• Pass --config=.lychee.toml explicitly in workflow args
• Remove pull_request trigger (push trigger already covers PR branches)
• Exclude live branch from push triggers (already validated on main)

[learn-build-service-prod]

Learn Build status updates of commit 60ac153:

✅ Validation status: passed

File	Status	Preview URL	Details
.github/workflows/linkchecker.yml	✅Succeeded
.lychee.toml	✅Succeeded

For more details, please refer to the build report.

[learn-build-service-prod]

PoliCheck Scan Report

The following report lists PoliCheck issues in PR files. Before you merge the PR, you must fix all severity-1 and severity-2 issues. The AI Review Details column lists suggestions for either removing or replacing the terms. If you find a false positive result, mention it in a PR comment and include this text: #policheck-false-positive. This feedback helps reduce false positives in future scans.

✅ No issues found

More information about PoliCheck

Information: PoliCheck | Severity Guidance | Term
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[learn-build-service-prod]

Learn Build status updates of commit d3e148e:

✅ Validation status: passed

File	Status	Preview URL	Details
.github/workflows/linkchecker.yml	✅Succeeded
.lychee.toml	✅Succeeded

For more details, please refer to the build report.

[learn-build-service-prod]

PoliCheck Scan Report

The following report lists PoliCheck issues in PR files. Before you merge the PR, you must fix all severity-1 and severity-2 issues. The AI Review Details column lists suggestions for either removing or replacing the terms. If you find a false positive result, mention it in a PR comment and include this text: #policheck-false-positive. This feedback helps reduce false positives in future scans.

✅ No issues found

More information about PoliCheck

Information: PoliCheck | Severity Guidance | Term
For any questions: Try searching the learn.microsoft.com contributor guides or post your question in the Learn support channel.