Sphinx-theme-builder

- Adopt the newer copy of `copyfileobj_with_hashing`
- Correctly encode `RECORD` hashes
- Document a previously undocumented error case
- Document the `--pdb` flag
- Improve documentation to pass nit-picks
- Improve the `autobuild-failed` documentation
- Use tomllib on Python 3.11+

- Add `--host` to `stb serve`.
- Document a theme asset management approach.
- Fix the generator value.
- Generate a `package-lock.json` file, if it does not exist.
- Switch to `pyproject-metadata` (from `pep621`).

- Add `--pdb` flag to `stb serve`.
- Accept more values for `STB_USE_SYSTEM_NODE`, error out on invalid ones.
- Add `STB_RELAX_NODE_VERSION_CHECK`.
- Fix typing-related import for Python 3.7 compatibility.
- Document all errors in the error index, describing what the user can do.
- Fix project source URL in metadata.
- Improve the getting started tutorial.
- Tweak how links are presented in errors.

- Don't pin the upper Python version.
- Present the traceback on Sphinx failures.
- Update error message for `nodeenv-creation-failed`
- Quote the `sys.executable`.
- Fix mis-formatted README opening.
- Back to development.

- Simplify system node usage logic.
- Use the correct binary directory on Windows.
- Reducing the size of the generated nodeenv.
- Add TODOs to the tutorial, to reflect it is incomplete.

- Fix Windows compatibility.