Function looks_like_launchd_default 

pub fn looks_like_launchd_default(path: &str) -> bool

True when the current PATH is the stripped launchd default (every entry is one of /usr/bin, /bin, /usr/sbin, /sbin) — i.e. a GUI launch that never saw the user’s shell. Used by the srv to decide whether the cheap guard should pay for a login-shell spawn on a direct launch.