Add git metadata appendix from lab-manual

[Copilot]

Ports the document generation metadata appendix from UCD-SERG/lab-manual. Displays git commit information (branch, hash, date) in rendered outputs for tracking source versions when transferring edits from rendered documents back to Quarto sources.

Changes

• New appendix: appendix-document-metadata.qmd executes R code at render time to capture git metadata
• Configuration: Added appendices section to _quarto.yml
• CI workflows: Added R environment setup and package installation (knitr, rmarkdown, tibble) to publish.yml and preview.yml

The tibble package is required by existing df-print: tibble configuration in _quarto.yml for PDF output.

Example output

- Branch: main
- Commit: a1b2c3d
- Full commit hash: a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t0
- Commit date: 2026-02-05 05:57:59 +0000

Original prompt

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This section details on the original issue you should resolve

<issue_title>add the git metadata section from https://github.com/UCD-SERG/lab-manual</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes add the git metadata section from https://github.com/UCD-SERG/lab-manual #29

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