Function clipboard_entries_from_paths 

fn clipboard_entries_from_paths(
    pack: &Pack,
    paths: &[ContainerPath],
    pack_key: &str,
) -> Vec<(String, String, String)>

Expand selected paths into file path entries for the clipboard.

Returns (file_path, base_path, source_pack_key) per file. Only paths are stored, not the file data itself — the actual RFile is cloned from the source pack at paste time.

• For a selected file a/b/c, the base path is a/b (parent folder), so pasting gives just c.
• For a selected folder a/b, the base path is a (parent of folder), so pasting preserves b/....