docs(CHANGES): Note ruff 0.16 floor (#63)

why: The unreleased entry tracks dev-tooling floors so contributors
know which linter version the repo's diagnostics assume.

what:
- Add a `### Development` bullet for the `ruff>=0.16.0` floor

Author: tony

CHANGES

@@ -98,6 +98,7 @@ matching reference material.
 - Root `conftest.py` remains type-checked while the temporary docs-extension [mypy](https://mypy-lang.org/) path excludes only the extension-local `docs/_ext/conftest.py` case that caused duplicate module discovery (#46).
 - The docs dependency pins track gp-sphinx through `0.0.1a17`, including the `exclude-newer` whitelist needed for the git-pull package family during coordinated pre-release work (#55).
 - Workflow actions moved to their current major releases: `actions/checkout` v7, `actions/cache` v6, `astral-sh/setup-uv` v9.0.0, `codecov/codecov-action` v7, and `dorny/paths-filter` v4. Workflow behavior is unchanged, though setup-uv no longer prunes the uv cache, so the first run after this repopulates it.
+- Minimum `ruff>=0.16.0` (was unpinned), so contributors and CI share the same lint diagnostics and the [ruff 0.16](https://astral.sh/blog/ruff-v0.16.0) formatting of Python code blocks inside Markdown (#63).
 
 ## g 0.0.9 (2026-01-24)