Function cache_path_for_save 

pub fn cache_path_for_save(save_path: &Path) -> PathBuf

Per-save cache path: ~/.nms-copilot/<account_dir>/<save_stem>/galaxy.rkyv.

Derives cache location from the save file path, using the parent directory name (account) and file stem (no extension) as path components. For example, …/st_76561198025707979/save3.hg becomes ~/.nms-copilot/st_76561198025707979/save3/galaxy.rkyv.