Don't Let Conda Eat Your Hard Drive: Python Environment Cleanup for Mac

My Anaconda installation was 28GB. I had 12 conda environments I'd forgotten about — one for every tutorial I'd followed, every Kaggle competition I'd started and abandoned, every "let me just try this library real quick" session. Each one had its own copy of NumPy, pandas, and scikit-learn. Three of them had PyTorch installed. That's 2-3GB per copy, sitting in folders I hadn't touched in months. If you do any data science or ML work on a Mac, you've been there. Python's environment model is des