Add Windows setup instructions to CONTRIBUTING.md

[castroquiles]

Our setup guide is macOS/Linux only. Add a Windows section covering conda activation and any gotchas. Expected outcome: a new Windows subsection in CONTRIBUTING.md. Difficulty: Easy

[q404365631]

Hi! I'd like to work on this. I'll add a Windows setup section to CONTRIBUTING.md covering conda activation and Windows-specific gotchas. Thanks!

[castroquiles]

Hey! Thanks for your interest in contributing that sounds great. Adding a Windows setup section with conda activation and any platform-specific tips would be really helpful. Feel free to open a PR when ready!