chore: upgrade docs tooling to latest stable; hide badges from the man page

[nandgator]

Rebased onto master after #495 merged.

Summary

#495 deliberately keeps the documentation tooling at the versions that produced the old output. This PR lifts that restriction and moves everything to the latest stable releases, then deals with what changes.

• Drop the upper bounds on the docs-offline and docs-online groups, and let ruff format Markdown again (ruff 0.17 formats Python blocks in .md files).
• uv lock --upgrade: sphinx 9, furo 2025.12.19, myst-parser 5.1, docutils 0.22.4, pypandoc-binary 1.17, mkdocstrings 1.0.6 and mkdocstrings-python 2.0.9.
• mkdocs: rename the mkdocstrings import: key to inventories:. import was deprecated in mkdocstrings-python 1.14 and removed in 2.0 (this was breaking mkdocs build). I checked every version from 1.10.5: the key is supported from 1.14.0, so the floor is mkdocstrings-python>=1.14.0. Builds with both 1.19.0 and 2.0.9.
• package/export: show the README badge row in html output only (see below).
• Regenerate the tracked docs (docs/index.rst, docs/install_and_use.{md,rst}).

Is the changed output a problem?

Regenerated with the real ./package/roll.sh and compared with the old output:

Change in the man page	Verdict
The five badge images rendered as [image: PyCQA] [image] <url> ...	Real regression (about 8 lines of noise at the top). Fixed here: the badge row is wrapped in .. only:: html, so the web docs keep their badges and the man page drops the row.
Hyperlinks now show their URL (Documentation <https://...>)	Improvement: the Resources links previously had no visible URL at all.
Code blocks use .EX/.EE instead of .nf/.ft C; the old groff "cannot select font 'C'" warnings are gone	Fine: needs groff 1.22.4 or newer, which any current Debian or Ubuntu has.
.SH Author / .SH Copyright instead of upper case	Cosmetic: docutils 0.22 emits these literally. Not patched around.
Note: instead of NOTE:, footer comments, spacing	Cosmetic.

Web docs: compared the visible article text of every page (the same 20 API pages plus index, install and use): identical. Only theme assets, version strings and boilerplate differ. docs/index.rst changes only in bullet whitespace (newer pandoc). docs/install_and_use.md gets a blank line and double quotes in its Python example from ruff.

Checked on this branch: package/export man, web and doc (mkdocs) all build with rc=0 and no new warnings (the import FutureWarning is gone); 1069 tests, ruff check, ruff format --check and pyright pass.

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