* chore: declare pytest as a uv dev dependency
The contributing guide currently tells contributors `pip install pytest`
as a separate step, and CI does the same. Move pytest into PEP 735
`[dependency-groups]` so it's declared in pyproject.toml and `uv sync`
installs it by default (no `--with` workaround, no separate install
line). Update CI to use astral-sh/setup-uv + `uv sync` + `uv run pytest`,
and refresh the Contributing section of the README to match.
`[dependency-groups]` is the right home (vs `[project.optional-dependencies]`)
because pytest is dev-only and shouldn't appear in the published wheel's
optional features list alongside things like `pdf` or `mcp`.
* remove uv.lock from gitignore
Brian K
244a266c06