feat: add JohnXu22786/docgen

[github-actions]

Plugin / 插件

• Repository: https://github.com/JohnXu22786/docgen
• Install: github:JohnXu22786/docgen
• Intent: plugin_submission
• Source issue: [Add Plugin] JohnXu22786/docgen #24

Admission checks / 录入检查

• 公开仓库 / Public repository
• 仓库处于可维护状态 / Repository is active
• package.json 可解析 / package.json parses
• 可识别为 DSH 插件 / Recognized as a DSH plugin through package.json:dsh.bundle
• README 包含安装或使用说明 / README includes installation or usage guidance
• dsh.bundle 文件引用完整 / dsh.bundle file references resolve
• 默认分支没有失败的代码检查 / No failing default-branch checks
• Registry source validation

Closes #24

[github-actions]

Governance review: needs_human · Risk: R1

• UNVERIFIED_MAINTAINER

Decision record: pr-53-e648937eb53d
Evidence SHA: c0b804b289f8363af9b28f1a3fb7304a49e56421

[Ericwong5021]

人工治理验收 / Maintainer governance review

• 分类已校正为 research-knowledge/document-processing，来源标记为 reviewed-override。
• 风险结论：R1。内容为文档生成与代码审查技能包，提交者与仓库所有者一致；未发现运行时依赖或高风险系统能力。
• 固定证据提交：c0b804b289f8363af9b28f1a3fb7304a49e56421。
• Registry schema、身份唯一性、路径范围、Immutable Evidence 与确定性校验均已通过。

同意人工 squash 合并；该结论不降低插件运行时应显示的权限与风险提示。 / Approved for manual squash merge; runtime permission and risk disclosures remain required.