docs(blog): correct the Chinese translation of "rehydrate"

[ggbdpq]

Summary

Fixes #4767. Corrects the Chinese translation of the runtime term rehydrate in docs/blogs/beyond-function-calling.zh-CN.md:

• prose: 水合（Rehydrate）→ 恢复执行状态（Rehydrate）;
• mixed-language diagram label: Rehydrate 会话上下文 → 恢复会话上下文（Rehydrate）, with the leading indent compensated so the box-drawing arrow tail stays aligned with the bar above;
• the two all-English diagram labels (lines 393, 454) keep the bare Rehydrate, per the acceptance criteria.

Only the zh-CN blog file is modified; the English article is untouched.

Verification

Claim	Command / route	Result
水合 no longer used	grep 水合 on the file	zero matches
Prose wording	line 405	恢复执行状态（Rehydrate）
Diagram label wording	line 425	恢复会话上下文（Rehydrate）, arrow tail visually aligned with the │ column above
English-only labels untouched	diff	lines 393 / 454 unchanged
Scope	git diff --stat	1 file, +2/−2
Format	npm run format:check	exit 0

AI use

Implemented with ZCode (GLM-5.3-Flash) per the issue's explicit acceptance criteria. The commit carries the Generated-by trailer.

Checklist

• Only docs/blogs/beyond-function-calling.zh-CN.md modified
• All six acceptance criteria from the issue met
• Refs #4767 in the commit message