[Li-Zhuo-Ran]

Summary

• Compared the introductory examples, Python syntax explanations, code comments, equations, and exercises with the English source.
• Clarified that each white-noise draw follows a standard normal distribution and the draws are mutually independent.

Validation

• git diff --check
• Confirmed code-cell, figure, exercise, solution, and hint directive counts match the English source.

Refs #88