numero2/contao-proper-filenames ? reverse-engineered prompt

Build me a Contao extension that cleans up uploaded file names right after upload, so special characters get replaced and people end up with safe, normal filenames. It should work for files uploaded through the Contao file manager and through Contao forms, and it should fit Contao 4.13 and newer, including Contao 5.

I also want a console command that can go through an existing folder and rename files and subfolders recursively, with a dry run option so I can preview the changes before anything is actually renamed. It should only work on files that are already known to Contao, so make sure it uses the file system data Contao keeps in sync.

Please include the backend setting where I can turn filename checking on and choose how valid characters should be handled. If anything depends on current Contao docs or best practices, look that up online and follow the usual Contao way of doing it.