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

backend/src/middleware/validateProject.ts

@@ -0,0 +1,110 @@
+import { FastifyRequest, FastifyReply } from 'fastify';
+
+interface CreateProjectBody {
+  name: string;
+  background?: string;
+  researchType: 'observational' | 'interventional';
+}
+
+interface UpdateProjectBody {
+  name?: string;
+  background?: string;
+  researchType?: 'observational' | 'interventional';
+}
+
+// 验证创建项目请求
+export async function validateProjectCreate(request: FastifyRequest, reply: FastifyReply) {
+  const body = request.body as CreateProjectBody;
+
+  // 验证必填字段
+  if (!body.name || typeof body.name !== 'string') {
+    return reply.code(400).send({
+      success: false,
+      message: '项目名称为必填项',
+    });
+  }
+
+  if (body.name.trim().length === 0) {
+    return reply.code(400).send({
+      success: false,
+      message: '项目名称不能为空',
+    });
+  }
+
+  if (body.name.length > 100) {
+    return reply.code(400).send({
+      success: false,
+      message: '项目名称不能超过100个字符',
+    });
+  }
+
+  // 验证研究类型
+  if (!body.researchType) {
+    return reply.code(400).send({
+      success: false,
+      message: '研究类型为必填项',
+    });
+  }
+
+  if (!['observational', 'interventional'].includes(body.researchType)) {
+    return reply.code(400).send({
+      success: false,
+      message: '研究类型必须是observational或interventional',
+    });
+  }
+
+  // 验证项目背景（可选，但有长度限制）
+  if (body.background && body.background.length > 2000) {
+    return reply.code(400).send({
+      success: false,
+      message: '项目背景不能超过2000个字符',
+    });
+  }
+}
+
+// 验证更新项目请求
+export async function validateProjectUpdate(request: FastifyRequest, reply: FastifyReply) {
+  const body = request.body as UpdateProjectBody;
+
+  // 至少需要更新一个字段
+  if (!body.name && !body.background && !body.researchType) {
+    return reply.code(400).send({
+      success: false,
+      message: '至少需要提供一个要更新的字段',
+    });
+  }
+
+  // 验证项目名称
+  if (body.name !== undefined) {
+    if (typeof body.name !== 'string' || body.name.trim().length === 0) {
+      return reply.code(400).send({
+        success: false,
+        message: '项目名称不能为空',
+      });
+    }
+
+    if (body.name.length > 100) {
+      return reply.code(400).send({
+        success: false,
+        message: '项目名称不能超过100个字符',
+      });
+    }
+  }
+
+  // 验证研究类型
+  if (body.researchType && !['observational', 'interventional'].includes(body.researchType)) {
+    return reply.code(400).send({
+      success: false,
+      message: '研究类型必须是observational或interventional',
+    });
+  }
+
+  // 验证项目背景
+  if (body.background && body.background.length > 2000) {
+    return reply.code(400).send({
+      success: false,
+      message: '项目背景不能超过2000个字符',
+    });
+  }
+}
+