Add Win32 UI Modernizer (#4800)

## Mod authorship

If this pull request introduces a new mod, please complete the section below.

This mod was created by:

- - [ ] The submitter, without AI assistance
- - [X] The submitter, with AI assistance
- - [X] Claude
- - [X] ChatGPT
- - [ ] Gemini
- - [ ] Another AI (please specify): 
- - [ ] Other (please specify): 

Please select the options that best apply. Your selection does not affect the acceptance criteria, but it helps reviewers understand the context of the code and provide relevant feedback.

Author: crazyboyybs