Update Python version requirement and add .cursorrules to .gitignore

[Wuhall]

Description: This PR makes two maintenance updates:

1. Explicitly states the Python version requirement in README.md
2. Adds .cursorrules to .gitignore to exclude editor-specific files

Changes: • Updated README.md to specify Python version compatibility

• Added .cursorrules to .gitignore for better developer experience

Checklist: • [x] My code follows the project's style guidelines

• [x] I have reviewed my own changes

• [x] I have updated documentation (README.md)

• [x] My changes generate no new warnings

[Wuhall]

@microsoft-github-policy-service agree

[afourney]

I generally agree with this, but I don't want to necessarily call out conda.

We should just have a section that mentions the version, and shows how to create a venv in several ways (e.g., uv, conda, etc.)