[vagenas]

Summary

Release 0.9.1: whitespace edge cases in doclang migrate (#228). Toolkit only; the spec is unchanged.

Prepared with uv run python utils/prepare_release.py 0.9.1:

• Version 0.9.1 in pyproject.toml and the XSD (doclang/doclang.xsd and doclang/schemas/0.9/doclang.xsd).
• Migration steps are not rotated, as the 0.9 schemas already exist.
• The Reference in spec.md is regenerated, with no change.
• CHANGELOG.md has a v0.9.1 section.

By hand:

• exports/*.docx: the regenerated files are not committed, as the spec is unchanged and they would lose the tables of contents updated in Word.
• uv.lock: only the doclang version line.

After merging

• GitHub release v0.9.1 on the merge commit (creates the tag)
• PyPI upload

Verified

• Full test suite (636 passed, 6 skipped), ruff and mypy.
• uv build: wheel and sdist 0.9.1, with the 0.7, 0.8 and 0.9 schemas and all migration steps; twine check passes.