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]

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[mmcky]

@jstac looking nice.

Here is a full build of the current intermediate lecture site with the updated headers

https://pr-726--sunny-cactus-210e3e.netlify.app/

and a example lecture

https://pr-726--sunny-cactus-210e3e.netlify.app/linear_algebra

[jstac]

Love your work @mmcky !!!

So nice to have this :-)

I'm doing a bit of work this morning on some of these lectures -- perhaps we can merge this in the afternoon? And then propagate to the other lecture series?

[mmcky]

Love your work @mmcky !!!

So nice to have this :-)

I'm doing a bit of work this morning on some of these lectures -- perhaps we can merge this in the afternoon? And then propagate to the other lecture series?

Roger that @jstac. I think it looks great too. I think @DrDrij would approve :-).

I will organise a new release now and then setup an upgrade PR.

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Preview URL: https://pr-726--sunny-cactus-210e3e.netlify.app (d42906e)

[mmcky]

@jstac merging this upgrade now.