Include TeachBooks-Fetch in the documentation and favourites list: add its MANUAL external link to book/_toc.yml and add a favourites entry in book/features/favourites.md so the extension is discoverable from the docs.
Add TeachBooks-Questions to the book TOC and TeachBooks Favourites list, and include Sphinx Gated Directives and TeachBooks Zoomies in the favourites page. Also tidy requirements.txt by removing an inline bump comment from the TeachBooks-Favourites git dependency. Changes touch book/_toc.yml, book/features/favourites.md, and requirements.txt to surface the new/manual links and clean up metadata.
Added new pages for Sphinx exercise and Sphinx proof extensions, including installation and usage instructions. Updated references, credits, and feature pages to reflect inclusion in TeachBooks Template and Favourites. Improved consistency of external links and badges, and updated submodules to latest versions.
Split the TeachBooks Python Package and Deploy Book Workflow documentation into dedicated intro pages (teachbooks_intro.md, DBW_intro.md), update references and links throughout feature pages, and revise the _toc.yml structure to include new sections. Added clarifications to favourites and live_code features, improving organization and navigation for users.
