Function atomcode_dir 

pub fn atomcode_dir() -> PathBuf

Return the atomcode data root ($ATOMCODE_HOME when set, or ~/.atomcode/ by default). Routes through crate::config::Config::config_dir so install/setup/skill/plugin/uninstall all agree on a single root — previously this module looked at a separate ATOMCODE_HOME_OVERRIDE variable, which let users customise their data dir but then lose track of it at uninstall time. One variable, one semantics.