Get rid of WinForms #5
Description
With Visual Studio officially supported on Macs and the input files often containing Windows serials that can be run on all kinds of platforms, it's time to make this less Windows-centric.
#4 moved the project from .NET Framework 4.5 to .NET 6 (LTS release at time of writing), but it still uses Winforms and thus only works on Windows still.
WPF? Maui? Uno? Avalonia? Let's use something other than WinForms so that this can be run natively on macOS and Linux.