* docs: migrate from mkdocs to mdbook
- Rename old mkdocs docs/ to old-docs/ for reference
- Set up new docs/ with mdbook (book.toml + src/ tree)
- Mirror full nav structure from mkdocs.yml into SUMMARY.md
- Add Justfile-docs with docs-serve, docs-build, docs-check, docs-install recipes
- Import Justfile-docs from root Justfile
- Rewrite .github/workflows/docs.yml: build step uses taiki-e/install-action
to install mdbook, split into separate build + deploy jobs, PR builds
run the check step too
* ci(docs): pin actions to SHAs, install mdbook via release binary
* ci(docs): install mdbook from apt instead of curling a release binary
* dev: replace mkdocs python stack with mdbook in dev image
* ci(docs): apt only works on Debian; restore release binary install for Ubuntu CI
* docs: fix duplicate file entries in SUMMARY.md
* docs: remove docs-install recipe
* docs: remove site-url from book.toml to fix asset loading
* dev: install mdbook from upstream release binary, not Debian apt
The Debian package (0.4.x+ds) strips bundled font assets, leaving the
built site without fonts/fonts.css. Use the upstream tarball (same as CI)
so the theme is complete. Handles x86_64 and aarch64.
* docs: vendor mdbook tarballs in dev/mdbook/, install from there
Dockerfile.dev uses COPY + tar to install the right arch at build time.
CI extracts the x86_64 tarball directly from the checkout.
No network access required for either — and no stripped-fonts Debian package.
* fix: unwritten
zk