* chore(release): 16.3.1

Cut 16.3.1 and refresh package metadata to match Tablassert's current
knowledge-graph and tabular-data feature set.

Patch: update PyPI keywords for KGX, Biolink, biomedical and tabular data,
quality control, and the optional LLM agent; add the Python 3-only library,
Pydantic 2, and supported implementation classifiers. Remove the misleading
`ner` and redundant package-name keywords. Keep the release metadata in sync
across `pyproject.toml`, `uv.lock`, and `CITATION.cff`.

Changelog:
- Added the `16.3.1 - 2026-09-03` entry documenting the PyPI metadata refresh.

Docs: none needed here; this release changes packaging metadata only.

Testing:
- `uv run pytest -q` -> 1073 passed, 38 skipped (87% coverage)
- `uv run ruff check . && uv run ruff format --check . && uv run pyright` -> clean / 0 errors, 0 warnings, 0 informations
- `uv lock --check` -> up to date (163 packages resolved)
- `uv run mkdocs build --strict` -> clean; upstream Material warning only

* docs(changelog): link the 16.3.1 entry to the pull request