feat: add frontend development guidelines and structure documentation

- Introduced API guidelines for interface contracts and request handling.
- Added design tokens usage guidelines for consistent styling across the project.
- Established DTO guidelines for defining request parameters and response data types.
- Created frontend structure guidelines to clarify directory organization and code placement rules.
- Compiled a comprehensive frontend development guideline document covering various aspects of the development process.
- Implemented quality guidelines to ensure code maintainability and adherence to best practices.

AI-RD-Workflow/50-cases/REQ-20260629-001-example/03-detailed-design/DS-20260629-001.md

@@ -0,0 +1,43 @@
+---
+id: DS-20260629-001
+case_id: REQ-20260629-001-example
+type: design-specification
+stage: detailed-design
+owner_role: RD
+status: draft
+source_ids:
+  - OR-20260629-001
+  - DR-20260629-001
+derived_ids:
+  - TASK-20260629-001
+  - TP-20260629-001
+created: 2026-06-29
+updated: 2026-06-29
+---
+
+# DS：详细设计
+
+## 影响范围
+
+新增 `AI Coding/AI-RD-Workflow/`，不修改现有文件。
+
+## 模块拆分
+
+- `00-meta`：元信息。
+- `10-standards`：规范。
+- `20-skills`：skill 草稿。
+- `30-templates`：模板。
+- `40-workflows`：工作流。
+- `50-cases`：需求实例。
+- `60-evaluations`：评测。
+- `90-archive`：归档。
+
+## 开发任务拆分
+
+- TASK-20260629-001：创建目录和初始文档。
+
+## 测试点
+
+- 检查目录是否存在。
+- 检查关键文档是否存在。
+- 检查示例 case 是否有完整追踪链路。