pub fn explain_sidecar(
run: &str,
dir: Option<&Path>,
json: bool,
) -> Result<String>Expand description
Diagnose Option-field absences for a run’s sidecars. Mirrors
show_run_host’s shape (--run + optional --dir,
printable string return). See the original rustdoc on the
public surface for the full JSON / text contract and exit-code
policy.