fn mtimes_and_files(paths: &[PathBuf]) -> (Vec<f64>, Vec<PathBuf>)Expand description
mtimes of every regular file in paths (directories walked recursively),
plus the top-level paths that are regular files.
One stat per path: on a drvfs/NAS workspace each one is a network round
trip, and the Episodes table in xil gui runs this for every episode.
Directory walks take the entry type from readdir and only stat what is
not a directory, which is what is_dir()/is_file()/stat() decide in
three calls in the Python.