`config policy show`, `config policy validate`, and `config plugins show`
are local-introspection-only commands kept behind the pruning
diagnostic whitelist so operators can always inspect why a command was
denied. They do not need to surface in `--help` for AI agents and were
contributing to help noise.
Hide the `policy` and `plugins` parent groups and both `show` /
`validate` leaves. Commands remain callable by exact name and continue
to bypass user-layer pruning via diagnosticPaths.