fix: backup site/ directory before branch switch in mkdocs workflow

[thomasht86]

The site/ directory built by mkdocs was lost when switching to gh-pages branch. Now backup to /tmp/site-backup before the branch switch and restore from there, matching the existing benchmark data backup pattern.

[claude]

PR Review: fix: backup site/ directory before branch switch in mkdocs workflow

Summary

This PR fixes a bug in the mkdocs deployment workflow where the site/ directory was being lost when switching to the gh-pages branch. The fix backs up the directory to /tmp/site-backup before the branch switch, matching the existing pattern used for benchmark data.

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Positive Feedback

1. Correct Problem Identification: The issue is real - git checkout gh-pages clears the working directory, including the freshly built site/ folder from line 33.

2. Consistent Pattern: The solution mirrors the existing benchmark data backup pattern (lines 46-56), maintaining consistency in the codebase.

3. Good Error Handling: The validation check (lines 65-68) ensures the backup exists before attempting to copy it.

4. Clear Commit Message: Follows conventional commits format and includes a co-author attribution.

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Code Quality Review

The fix is simple and straightforward - backs up site/ to /tmp/site-backup before branch switch, then restores from backup. Quality assessment: Good - proper validation before use and matches existing patterns.

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Potential Issues and Suggestions

1. Error Message Accuracy (Minor) - Line 66: The error message says "Error: site/ directory is empty or missing" but it's actually checking /tmp/site-backup. Consider: "Error: /tmp/site-backup directory is empty or missing (mkdocs build may have failed)"

2. Cleanup Consideration (Enhancement): The /tmp/site-backup directory persists after workflow completion. While not critical in CI environments (fresh runners each time), cleanup would be more hygienic. Optional: add rm -rf /tmp/site-backup at the end. Very low priority.

3. Defensive Check (Belt-and-suspenders): Consider verifying the site/ directory exists before backing it up. This would catch mkdocs build failures earlier with a clearer error message.

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Security Review

No security concerns identified - uses /tmp appropriately for CI, no user input handling, no credential exposure, proper GitHub Actions permissions.

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Test Coverage

No automated tests for GitHub Actions workflows (normal for most projects). The fix can be validated by checking that the next docs deployment successfully publishes to gh-pages. Consider triggering a manual workflow run to validate.

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Overall Assessment

Status: APPROVE with minor suggestions

This is a solid fix that correctly addresses the identified issue. The implementation is clean, follows existing patterns, and doesn't introduce any bugs or security concerns.

Recommended Actions:

1. Merge as-is - The PR is good enough to merge
2. Optional: Consider the error message improvement for better debugging
3. Optional: Add early validation of site/ directory before backup

Risk Level: Very Low
Merge Confidence: High

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Great work fixing this! The approach is sound and the implementation is clean.