chore(docs): remove the pre-mike Sphinx site from the gh-pages root

[LukasGold]

Closes #205.

Note on the base branch

This targets gh-pages, not main. Issue #205 is not a source change: the
leftovers live only on the build-output branch.

Changes

Removes 18 root entries, 63 files, deletions only. No file is added or
modified.

404.html, Makefile, assets, auth, authors, changelog, conf.py,
contributing, controller, license, model, objects.inv, osw,
readme, requirements.txt, search, tools, tutorials

The root tree goes from 53 entries to 35.

Rationale

These are a complete copy of the Sphinx site deployed before mike. Every entry
is byte-identical to
641d919,
the last Sphinx deployment, on 2026-07-07. They will never update again.

They are worse than absent. An unversioned path returns 200 and serves a
superseded page, so checking a documentation link by status code passes while
the reader sees content from July.

404.html is included for a separate reason. GitHub Pages serves a custom 404
only from the root copy, so this file is the live 404 page. Its assets point at
/Tools/assets/... while the site is served at /osw-python/, a wrong
site_url at build time. Every asset it requests returns 404, so it has never
rendered correctly. After removal, Pages serves its own 404 page. mike writes a
correct latest/404.html, but Pages ignores per-directory copies.

Kept

• .nojekyll. Its blob matches the July one only because the file is empty.
• Everything mike writes: index.html, versions.json, sitemap.xml,
  sitemap.xml.gz, dev, latest, and the version directories 2.0.0 to
  2.8.0.

Nothing under latest/, dev/ or any version directory is touched.

URLs that change from 200 to 404

The Sphinx layout differs from the current one, so several have no
same-named replacement.

Removed	Current equivalent
/tools/	/latest/tools/
/tutorials/	/latest/tutorials/
/osw/	/latest/api/core/
/controller/	/latest/api/controller/
/model/	/latest/api/model/
/auth/	/latest/api/auth/
/license/, /authors/	/latest/about/
/contributing/, /changelog/, /readme/, /search/	none

CI

gh-pages carries no .github/ directory and no pyproject.toml, so no
workflow runs on a pull request against it. No checks will appear. The merge
triggers a Pages build, which publishes the pruned root.

[simontaurus]

ideally non-existing old url redirect to the main page, but since the documentation was not much used previously not a critical point