Migrate to uv

[PeterJCLaw]

uv is fast, pip-like and supports more modern python packaging approaches.

Build comparison helper:

srg srcomp && \
    rm -rf dist dist-uv && \
    script/release/build.sh && \
    mv dist dist-uv && \
    pushd dist-uv && \
    unzip sr_comp*-py3-none-any.whl -d wheel && \
    mkdir -p tar.gz && \
    tar --extract --file sr_comp*.tar.gz --directory=tar.gz && \
    popd && \
    diff -r dist-setuptools dist-uv > pkgs.diff ; \
    echo "Done: $?"