feat: 重构项目心跳数据结构并实现项目列表API

- 新增统一项目列表Redis键和迁移工具
- 实现GET /api/projects端点获取项目列表
- 实现POST /api/projects/migrate端点支持数据迁移
- 更新前端ProjectSelector组件使用真实项目数据
- 扩展projectStore状态管理
- 更新相关文档和OpenSpec规范
- 添加测试用例验证新功能

AGENTS.md

@@ -1,18 +1,21 @@
 <!-- OPENSPEC:START -->
+
 # OpenSpec Instructions
 
 These instructions are for AI assistants working in this project.
 
 Always open `@/openspec/AGENTS.md` when the request:
+
 - Mentions planning or proposals (words like proposal, spec, change, plan)
 - Introduces new capabilities, breaking changes, architecture shifts, or big performance/security work
 - Sounds ambiguous and you need the authoritative spec before coding
 
 Use `@/openspec/AGENTS.md` to learn:
+
 - How to create and apply change proposals
 - Spec format and conventions
 - Project structure and guidelines
 
 Keep this managed block so 'openspec update' can refresh the instructions.
 
-<!-- OPENSPEC:END -->
+<!-- OPENSPEC:END -->