docs: refresh multilingual readmes

[iAlexKai]

Summary

• replay the finalized benchmark README updates across English, Chinese, and Japanese
• restore the academic backing section in all three README files with the public arXiv link for VikingMem
• keep the previously confirmed multilingual structure and formatting aligned

Validation

• git fetch origin main
• git merge --ff-only origin/main
• git diff --check -- README.md README_CN.md README_JA.md
• GetDiagnostics on the three edited README files

[github-actions]

PR Reviewer Guide 🔍

(Review updated until commit ffa6ec8)

Here are some key observations to aid the review process:

⏱️ Estimated effort to review: 1 🔵⚪⚪⚪⚪

🏅 Score: 95

🧪 No relevant tests

🔒 No security concerns identified

✅ No TODO sections

🔀 No multiple PR themes

⚡ Recommended focus areas for review Broken Anchor Link The anchor link in the May 2026 update banner has an extra leading hyphen, which likely breaks navigation to the evaluation results section. ✨ **2026年5月更新**：更新 OpenViking 在 User Memory、Agent Memory 和知识库问答三场景上的评测结果。→ 见 [评测结果](#-评测结果)。

[github-actions]

PR Code Suggestions ✨

No code suggestions found for the PR.

[ZaynJarvis]

lgtm

[github-actions]

Persistent review updated to latest commit ffa6ec8

[github-actions]

PR Code Suggestions ✨

No code suggestions found for the PR.

[ZaynJarvis]

lgtm