pub fn sidecar_path(crate_name: &str) -> Option<PathBuf>Expand description
Resolve $HOME/.truce/shell/<crate_name>.path for a given crate.
crate_name is the consuming crate’s CARGO_PKG_NAME - the
reader passes env!("CARGO_PKG_NAME") and the writer passes the
resolved plugin’s crate_name from truce.toml. Returns None
when neither HOME (Unix) nor USERPROFILE (Windows) is set -
the caller should fail loud rather than guess a path.