feat: Day 8-9 - Project Management API completed

Backend:
- Create project routes (GET, POST, PUT, DELETE)
- Implement projectController with CRUD operations
- Create projectService for database operations
- Add validation middleware for request validation
- Update Prisma schema (add background, researchType, deletedAt fields)
- Implement soft delete for projects

Frontend:
- Create projectApi service module
- Update useProjectStore with fetchProjects and loading state
- Connect ProjectSelector to real API with loading indicator
- Connect CreateProjectDialog to real API with error handling
- Connect EditProjectDialog to real API with loading state
- Add comprehensive error handling and user feedback

Build: Both frontend and backend build successfully

frontend/src/stores/useProjectStore.ts

@@ -1,4 +1,6 @@
 import { create } from 'zustand';
+import { projectApi } from '../api/projectApi';
+import { message } from 'antd';
 
 export interface Project {
   id: string;
@@ -16,6 +18,9 @@ interface ProjectState {
   // 所有项目列表
   projects: Project[];
   
+  // 加载状态
+  loading: boolean;
+  
   // 是否显示创建项目对话框
   showCreateDialog: boolean;
   
@@ -30,11 +35,14 @@ interface ProjectState {
   deleteProject: (id: string) => void;
   setShowCreateDialog: (show: boolean) => void;
   setShowEditDialog: (show: boolean) => void;
+  setLoading: (loading: boolean) => void;
+  fetchProjects: () => Promise<void>;
 }
 
 export const useProjectStore = create<ProjectState>((set) => ({
   currentProject: null,
   projects: [],
+  loading: false,
   showCreateDialog: false,
   showEditDialog: false,
   
@@ -65,5 +73,25 @@ export const useProjectStore = create<ProjectState>((set) => ({
   setShowCreateDialog: (show) => set({ showCreateDialog: show }),
   
   setShowEditDialog: (show) => set({ showEditDialog: show }),
+  
+  setLoading: (loading) => set({ loading }),
+  
+  // 获取项目列表
+  fetchProjects: async () => {
+    try {
+      set({ loading: true });
+      const response = await projectApi.getProjects();
+      if (response.success && response.data) {
+        set({ projects: response.data });
+      } else {
+        message.error(response.message || '获取项目列表失败');
+      }
+    } catch (error) {
+      console.error('获取项目列表失败:', error);
+      message.error('获取项目列表失败');
+    } finally {
+      set({ loading: false });
+    }
+  },
 }));