Upgrade quantecon-book-theme to 0.12.0 with git metadata

[mmcky]

This PR upgrades quantecon-book-theme from 0.11.0 to 0.12.0, which includes:

New Features in 0.12.0

• Improved lecture header layout with git-based metadata
• Last changed timestamp showing the date of the most recent commit
• Commit history dropdown showing the last 10 commits
• Clickable commit hashes linking directly to GitHub
• Full commit history link for complete version tracking

Configuration Changes

• Added path_to_docs: lectures to enable proper GitHub links to source files

The CI build will provide a preview of the new theme features before merging.

Release: https://github.com/QuantEcon/quantecon-book-theme/releases/tag/v0.12.0

[github-actions]

🚀 Deployed on https://6922965ec4efd2a4e5504ab6--epic-agnesi-957267.netlify.app

[mmcky]

@jstac I am doing a full execution check to see the preview generated + git results (c731a33)

I have to head out now, but will check this build as soon as I'm back this afternoon.

[mmcky]

@jstac looks like I'll need to take a closer look at this deployment to understand why only one git element is showing up.

[mmcky]

Fix: Enable Full Git History for Changelog Feature

Added fetch-depth: 0 to both CI workflows to fetch full git history instead of shallow clones.

Changes

• ci.yml: Added fetch-depth: 0 to checkout step
• publish.yml: Added fetch-depth: 0 to checkout step

Why This Was Needed

The new changelog feature in quantecon-book-theme v0.12.0 displays the last 10 commits for each document. By default, GitHub Actions uses shallow clones (fetch-depth: 1) which only includes the most recent commit, causing the changelog to show only 1 commit instead of 10.

This matches the configuration used in lecture-python.myst which already has full git history enabled in its CI workflow.

Result

The changelog dropdown will now show up to 10 commits (configurable) for each lecture page instead of just 1.

[mmcky]

@jstac all fixed. The ci was just fetch a depth of 1 for the clone on GitHub actions.