Add missing dependencies to requirements.txt

- Added scipy>=1.10.0 (used for statistical functions)
- Added statsmodels>=0.14.0 (used for statistical tests)
- Added Pillow>=9.5.0 (used for image processing)

These dependencies are used in the Python code examples and were missing from the requirements file.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: alexanderthclark

jupyterbook/requirements.txt

@@ -8,6 +8,11 @@ matplotlib>=3.7.0
 numpy>=1.24.0
 pandas>=2.0.0
 scikit-learn>=1.3.0
+scipy>=1.10.0
+statsmodels>=0.14.0
+
+# Image processing
+Pillow>=9.5.0
 
 # For better notebook execution
 nbclient>=0.5.0