Support kube-score

[kube-score](https://github.com/zegl/kube-score) is a great project that: "Kubernetes object analysis with recommendations for improved reliability and security". can add it as scoring functionality.

Start by reviewing the repository's existing scoring integrations and the kube-score documentation to understand the expected integration boundary. Define what kube-score support should report, then verify that its results are incorporated into ValidKube's output and covered by the repository's existing checks.

Written by the indexing model from the issue text.