Function pipe_name 

pub fn pipe_name(data_dir_hash16: &str) -> String

Construct the named-pipe path for a given data-dir hash. Format: \\.\pipe\agentmux-{hash16}\command.

Per-data-dir scoping preserves multi-instance support per CLAUDE.md: different portable folders / installed versions → different data dirs → different hashes → distinct pipes. Two launchers pointing at the SAME data dir will collide on the pipe name, which is also the single-instance signal Phase B.6 relies on.