The boost::nowide library does not provide a UTF‑8 aware stat function, unlike many of its other I/O…

The boost::nowide library does not provide a UTF‑8 aware stat function, unlike many of its other I/O…: a task in LegoFlow-SWE (Harbor dataset). We therefore need a public stat function in the boost::nowide namespace that accepts UTF‑8 paths and behaves correctly on all platforms.