docs: Add user guide for primitives module in English and Chinese

Signed-off-by: FrozenlemonTee <1115306170@qq.com>

Author: FrozenLemonTee

docs/guide/en/README.md

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+# primitives User Guide (English)
+
+This section is organized by workflow. Start with installation, then quick start.
+
+## Reading Order
+
+1. [Installation and Build](./installation-and-build.md)
+2. [Quick Start](./quick-start.md)
+3. [Concurrency Guide](./concurrency.md)
+4. [Extension Guide](./extension.md)
+
+## Related Docs
+
+- API reference: [../../api/en/README.md](../../api/en/README.md)
+- Docs root: [../../README.md](../../README.md)

docs/guide/zh/README.md

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+# primitives 用户文档（中文）
+
+本节按使用流程组织。建议先看安装构建，再看快速上手。
+
+## 阅读顺序
+
+1. [安装与构建](./installation-and-build.md)
+2. [快速上手](./quick-start.md)
+3. [并发使用指南](./concurrency.md)
+4. [扩展开发指南](./extension.md)
+
+## 相关文档
+
+- API 参考： [../../api/zh/README.md](../../api/zh/README.md)
+- 文档总入口： [../../README.md](../../README.md)