Translate evaluation docs to Chinese

[CaralHsi]

The evaluation documentation currently exists only in English. This issue is to add Chinese translations for the evaluation docs.

Files to translate

Translate:

• docs/en/open_source/evaluation/overview.md
• docs/en/open_source/evaluation/openai_memory_locomo_eval_guide.md

Place the translated files under:

• docs/cn/open_source/evaluation/overview.md
• docs/cn/open_source/evaluation/openai_memory_locomo_eval_guide.md

Requirements

• Preserve command examples and script paths exactly.
• Keep dataset names such as LoCoMo, LongMemEval, PrefEval, and PersonaMem unchanged.
• Use clear Chinese explanations for setup, configuration, and evaluation workflow.
• Ensure relative links still work from the new Chinese docs location.

Acceptance Criteria

• Both Chinese evaluation pages are added.
• Markdown formatting is valid.
• Code blocks and commands remain unchanged.
• Links between the overview page and the OpenAI Memory guide work correctly.

[GoofySatoshi]

Hey, I'm interested in contributing and would love to take this translation issue. I've read the docs contribution guide and will ensure all commands, paths, and technical terms remain unchanged. Can you please assign this to me? Thanks!

[Memtensor-AI]

✅ AutoDev task 793d509bc4eb60ee completed.

Summary: 已完成 evaluation 文档的中文翻译：新增 docs/cn/open_source/evaluation/overview.md 与 openai_memory_locomo_eval_guide.md，保留了 LoCoMo / LongMemEval / PrefEval / PersonaMem 等数据集名、所有命令与脚本路径，以及 ../../../../evaluation/scripts/... 相对链接（已校验可解析到仓库根的 evaluation/scripts/）。Commit 已 push 到 autodev/MemOS-1692。

Base branch: v2.0.16
Branch: autodev/MemOS-1692
Commit: 2385421
PR: #1819
Assigned to: @CarltonXiang, @syzsunshine219
Reviewers: @CarltonXiang, @syzsunshine219