With detailed Chinese comments for easy learning

[lioZ129]

Description

I have added detailed Chinese comments to the entire codebase to facilitate a better understanding of the underlying mechanisms.

Purpose: To serve as a comprehensive guide for learners who want to understand how NanovLLM is built from scratch.

Note:

• Zero Logic Change: I have strictly added comments only. No code logic has been modified.
• Practical Clarity: It documents some questions that emerged and in-depth insights gained during my source code review.
• Branching: If you wish to preserve the code's conciseness, this can be maintained as a separate branch to serve as an annotated guide.