Function export_file_with_fork 

pub fn export_file_with_fork(
    fs: &mut dyn Filesystem,
    entry: &FileEntry,
    dest_dir: &Path,
    out_name: &str,
    mode: ResourceForkMode,
) -> Result<u64>

Export one FILE entry into dest_dir under the base name out_name (already sanitized / suffixed by the caller — e.g. the browse view appends a ProDOS #TTAAAA suffix), using mode. Returns the number of bytes written (data + resource) for progress accounting. The caller handles directories (create + recurse). Use safe_name for the default sanitized name.