v2.2.0

Added

• Command::prefer_local(dir) — a directory to probe before the system
• ProcessStdin::send_control(char) — validates and writes a single control

Fixed

• Priority docs — the Unix privilege caveat ("lowering nice below its
• Windows ProcessGroup::{suspend, resume} no longer risk freezing an unrelated
• wait_for / wait_for_port now background-drain the child's piped