Match prek additional_dependencies and pyproject dev pins to pdm.lock (ruff==0.15.22, basedpyright==1.39.9). Format fix for ruff 0.15.22.
Add prek.toml so git commit runs ruff-pre-commit (fix then format) and pdm-based basedpyright. Document install/install-hook; clear type warnings that made basedpyright exit non-zero under recommended mode.