Hey guys,

I'm currently learning Python and PyQt5. To practice, I built a small desktop app that works with APIs and handles local data.

Since I want to improve my code quality and learn best practices, I'd really appreciate some help and code review:

1. Is my PyQt5 structure written properly (signals/slots, layouts)?
2. How can I better separate the backend/API logic from the GUI components?
3. Are there any unpythonic bad practices or PEP8 issues in my code?

Here is my code on GitHub: https://github.com/MrAJDebug/disk_cleaner

Thanks for helping me learn!