ultrahdr_app throws an error when trying to write a path with Chinese characters

It appears the CLI tool cannot handle some valid characters in paths, such as the Chinese character below.

Using the command line flag:
`-z \"C:\Users\admin\Documents\張\out.jpg"`

Will show an error message:
**unable to write to file: C:\Users\admin\Documents\?\out.jpg**

This fails under Windows 11, but seems to work OK under MacOS.

_Note that other less common characters in EU languages will work in the CLI app (if they exist on the disk) - but if the path fails for other reasons, the error message will be mangled. For example, "À" shows as "└" in the path listed in the error. So the error message itself does not correctly list the path in some cases where the character itself is supported._