[backend] fix: 修复异常处理和类型转换问题

frontend/src/pages/Dashboard/Dashboard.jsx

@@ -1,5 +1,4 @@
 import React, { useEffect, useState } from 'react';
-import { authAPI } from '../../services/auth';
 import { projectAPI } from '../../services/project';
 
 const Dashboard = () => {

frontend/src/pages/Projects/ProjectList.jsx

@@ -1,10 +1,11 @@
 import React, { useState, useEffect } from 'react';
+import { useNavigate } from 'react-router-dom';
 import { useAuth } from '../../contexts/AuthContext';
 import { projectAPI } from '../../services/project';
 
 const ProjectList = ({ mode = 'list' }) => {
-  const { user } = useAuth();
   const navigate = useNavigate();
+  const { user } = useAuth();
   const [list, setList] = useState([]);
   const [total, setTotal] = useState(0);
   const [loading, setLoading] = useState(false);

frontend/src/pages/Statistics/Statistics.jsx

@@ -1,5 +1,4 @@
 import React, { useState, useEffect } from 'react';
-import { authAPI } from '../../services/auth';
 import { projectAPI } from '../../services/project';
 
 const Statistics = () => {