docs: add bilingual README

- add an English README and a Chinese translation with cross links,
  following the standard README.zh-CN.md convention
- cover packages, install prerequisites (authorizer chain), development
  workflow, and license

README.zh-CN.md

@@ -0,0 +1,46 @@
+# pi-extensions
+
+[English](README.md) | 简体中文
+
+[pi](https://www.npmjs.com/package/@earendil-works/pi-coding-agent) 编码代理的个人扩展集，专注 Bash 权限：放行前拆包、审视、再审。
+
+## 包
+
+| 包 | 说明 |
+|---|---|
+| [pi-permission-ai-judge](packages/pi-permission-ai-judge) | AI 判官。模型对每条待确认的 Bash 命令给出 allow / deny / defer；shadow 只记日志，enforce 代批放行 |
+| [pi-permission-inner-cmd](packages/pi-permission-inner-cmd) | 解包透明包装命令（`timeout`、`time` 等），按内层命令授权 |
+
+## 安装
+
+```bash
+pi install git:github.com/SikongJueluo/pi-extensions
+```
+
+包清单（根 `package.json` 的 `pi.extensions`）声明式挂载两个扩展，任意目录生效。前提：
+
+1. 启用 [`@gotgenes/pi-permission-system`](https://github.com/gotgenes/pi-permission-system) ≥ 32
+2. 把扩展挂进授权链——顺序即咨询顺序，仅 UI 会话生效：
+
+```jsonc
+// ~/.pi/agent/extensions/pi-permission-system/config.json
+{ "authorizerChain": ["inner-cmd", "ai-bash-judge"] }
+```
+
+ai-judge 的模式、判官模型与防线见其 [README](packages/pi-permission-ai-judge/README.md)。
+
+## 开发
+
+pnpm workspace，TypeScript + vitest。
+
+```bash
+pnpm install
+pnpm check   # tsc --noEmit
+pnpm test    # vitest run
+```
+
+设计决策见 [docs/adr/](docs/adr/)。
+
+## License
+
+GPL-3.0