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/60-evaluations/retrospectives/index.md

@@ -0,0 +1,18 @@
+---
+id: RETROSPECTIVES-INDEX
+type: evaluation-index
+status: draft
+created: 2026-06-29
+---
+
+# 复盘
+
+记录真实使用后的经验。
+
+每次复盘关注：
+
+- 哪个阶段卡住。
+- 哪个模板字段不够。
+- 哪个 skill 指令不清晰。
+- 哪个追踪关系缺失。
+- 是否需要更新标准、模板或 skill。