Refine Chinese copy on AI4AI survey page and homepage (#28)

- Clarify distinction between atomic execution and end-to-end self-iteration
- Eliminate buzzwords, em dashes, and robotic phrasing
- Sharpen academic tone around decision-making bottlenecks in AI4AI

Co-authored-by: yesiyu.andy <yesiyu.andy@bytedance.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

Author: 3 people