Function remote_worker_binary_path 

pub fn remote_worker_binary_path(
    user: &str,
    declared_os: Option<&str>,
) -> String

The canonical ABSOLUTE path to the deployed rch-wkr binary for a remote user and host OS. Unix workers use /root or /home/<user>; Windows workers run under Git Bash and use /c/Users/<user> plus the native .exe suffix. The probe script shell-quotes this path, so it MUST be absolute: a literal ~/.local/bin/... would be single-quoted and never expand, making [ -x ... ] fail and every worker look like it has a missing binary. Single source of truth for both the daemon bypass-recovery prober and the rch self-test --smoke capability scenario.