pub fn probe_version(program: &str) -> Option<String>Expand description
Ask a CLI for its version, on the augmented PATH. None when it cannot be
run, exits non-zero, or says nothing — each of which means the same thing to
a caller: this is not an installed, working CLI.
Every adapter wrapping a CLI needs exactly this, and it is the probe that
decides whether a harness reads as installed at all — so it lives once,
beside hidden_command and augmented_path, rather than being
copied per adapter and drifting.