Function validate_exec_profile_command 

pub fn validate_exec_profile_command(
    profile: &str,
    command: &[String],
) -> Result<()>

Validate a [exec.profiles.<name>] entry’s command: it must be a non-empty argv array. Surfaced for the config validation path so gwm config validate / gwm doctor reject what gwm exec --profile would (issue #324 review).