docs(changelog): add v0.3.1 release changelog (EN + ZH)

[fslongjin]

• Summarize 14 commits from 7 contributors since v0.3.0
• Features: custom sandbox network CIDR, systemd 255 compatibility, glibc preflight check, PVM consistency pre-check, AgentHub snapshot/rollback API and preview UI
• Fixes: network-agent restart sandbox network drop, host DNS switchover deadlock, OpenCloudOS image 9.4->9.6
• Docs: SA9.4XLARGE32 PVM benchmark, BMI5 real benchmark data, v0.3.0 release blog post, trpc-agent-go use case, disk space requirement update (300GB->50GB), duplicate Quick Start cleanup
• Update changelog index pages (EN + ZH) with v0.3.1 entry

[cubesandboxbot]

Claude finished @fslongjin's task in 26s —— View job

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Changelog Review: v0.3.1 Release (EN + ZH)

This is a post-merge review of the v0.3.1 release changelog. The PR has already been merged — the following are observations and suggestions for future changelog iterations.

✅ What Looks Good

• Consistent structure: Both the English and Chinese versions follow the same logical flow — executive summary, enhancements, bug fixes, documentation, and contributors. This alignment across languages is clean and maintainable.

• Detailed, actionable entries: Each changelog entry references the specific PR/issue number (e.g., #451, #442) and includes enough technical context for readers to understand the why behind each change. The network-agent fix (network-agent: fix existing sandbox network drop on restart #442) is a particularly good example of this: it explains the root cause (TUNSETIFF + IFF_ONE_QUEUE → EBUSY), the symptom (silent egress drop), and the fix.

• Contributor attribution: Listing all 7 contributors at the bottom with GitHub handles is a nice touch that gives credit where it's due.

• Index page updates: Both docs/changelog/index.md and docs/zh/changelog/index.md correctly add the v0.3.1 entry at the top of the table.

🔍 Observations & Suggestions

For future changelogs:

1. Add a brief migration/upgrade notes section when there are breaking or behavior-changing items. For example:

   • The OpenCloudOS 9.4→9.6 image change (fix(dev-env): update default OpenCloudOS image to 9.6-20260514.2 (9.4 download fails) #447) might affect users pinning to a specific image version
   • The glibc >= 2.34 preflight check (feat(one-click): add glibc version preflight check to fail fast on unsupported distros #457) could surprise users on older distros if they aren't following the repo closely

2. Consider linking to the full diff at the top so readers can explore the raw changes: https://github.com/TencentCloud/CubeSandbox/compare/v0.3.0...v0.3.1

3. Repository spot check: Since this is a post-merge review, I verified that the referenced files exist on disk and the index pages correctly link to the new changelog files. Everything checks out.

📂 Files Reviewed

File	Status
docs/changelog/v0.3.1.md	✅ Added (47 lines)
docs/zh/changelog/v0.3.1.md	✅ Added (47 lines)
docs/changelog/index.md	✅ Modified (added v0.3.1 entry)
docs/zh/changelog/index.md	✅ Modified (added v0.3.1 entry)

Summary

The changelog is well-written, thorough, and properly structured. No changes are needed — this is a solid release documentation PR. 👍