Function enumerate_seed_with_progress 

pub fn enumerate_seed_with_progress(
    seed: &Path,
    on_dir: &mut dyn FnMut(),
) -> Vec<Cache>

Same as enumerate_seed but invokes on_dir once per directory entry observed during each child cache’s walk. Drill-in workers use this to feed Msg::ScanProgress to the TUI so the spinner counts folders the same way the startup scan does.