feat: Day 10-11 - Agent Configuration System completed

Backend:
- Create agents.yaml config file with 12 agents definition
- Create Prompt templates for topic-evaluation agent
- Implement agentService.ts for loading and managing agent configs
- Create agentController.ts with CRUD operations
- Create agent routes (GET /agents, /agents/:id, etc.)
- Register agent routes in main server

Frontend:
- Create agentApi.ts service module
- Update AgentChatPage to dynamically load agent config from API
- Add loading state and error handling
- Display agent details (description, category, model)

Build: Both frontend and backend build successfully

backend/prompts/topic_evaluation_user.txt

@@ -0,0 +1,15 @@
+请对以下研究选题进行评价：
+
+## 项目背景
+{{projectBackground}}
+
+## 研究选题
+{{userInput}}
+
+{{#if knowledgeBaseContext}}
+## 参考文献（来自知识库）
+{{knowledgeBaseContext}}
+{{/if}}
+
+请根据创新性、临床价值、科学性和可行性四个维度，对上述选题进行全面评价，并给出改进建议。
+