refactor: 移除登录信息在localStorage中的保存，改为仅使用cookies验证

- 移除 auth store 中所有 localStorage 相关代码（loadUserFromStorage、saveUserToStorage、clearUserFromStorage）
- 简化 setUserState 和 clearUserState，不再操作 localStorage
- 修改 initAuth 逻辑，只依赖 cookies 验证登录状态，不再从 localStorage 恢复
- 移除 HomePage.vue 和 Signup.vue 中注册成功后的 localStorage 保存
- 登录状态完全由后端 cookies 控制，提高安全性

src/shared/stores/auth.ts

@@ -8,8 +8,6 @@ export interface User {
   user_type: string
 }
 
-const STORAGE_KEY = 'auth_user'
-
 export const useAuthStore = defineStore('auth', () => {
   const user = ref<User | null>(null)
   const loading = ref(false)
@@ -25,49 +23,16 @@ export const useAuthStore = defineStore('auth', () => {
            error?.message?.includes('Cookie已过期')
   }
 
-  // 从 localStorage 加载用户信息
-  const loadUserFromStorage = (): User | null => {
-    try {
-      const stored = localStorage.getItem(STORAGE_KEY)
-      if (stored) {
-        return JSON.parse(stored)
-      }
-    } catch (error) {
-      console.error('从 localStorage 加载用户信息失败:', error)
-    }
-    return null
-  }
-
-  // 保存用户信息到 localStorage
-  const saveUserToStorage = (userInfo: User) => {
-    try {
-      localStorage.setItem(STORAGE_KEY, JSON.stringify(userInfo))
-    } catch (error) {
-      console.error('保存用户信息到 localStorage 失败:', error)
-    }
-  }
-
-  // 清除 localStorage 中的用户信息
-  const clearUserFromStorage = () => {
-    try {
-      localStorage.removeItem(STORAGE_KEY)
-    } catch (error) {
-      console.error('清除 localStorage 用户信息失败:', error)
-    }
-  }
-
-  // 设置用户状态（统一的状态更新方法，保存到localStorage）
+  // 设置用户状态（只更新内存状态，不保存到 localStorage）
   const setUserState = (userInfo: User) => {
     user.value = userInfo
     isAuthenticated.value = true
-    saveUserToStorage(userInfo)
   }
 
   // 清除用户状态
   const clearUserState = () => {
     user.value = null
     isAuthenticated.value = false
-    clearUserFromStorage()
   }
 
   // 验证并更新用户信息
@@ -131,21 +96,8 @@ export const useAuthStore = defineStore('auth', () => {
         }
       }
 
-      // 如果cookie验证失败或没有cookie，尝试从localStorage恢复
-      const storedUser = loadUserFromStorage()
-      if (storedUser) {
-        user.value = storedUser
-        isAuthenticated.value = true
-        // 尝试在后台验证用户信息，失败也不影响当前状态
-        validateAndUpdateUser().catch(() => {
-          // 静默失败，保持localStorage中的状态
-        })
-      } else {
-        // 既没有cookie也没有localStorage，清除认证状态
-        if (isAuthenticated.value) {
-          clearUserState()
-        }
-      }
+      // 如果没有cookie或cookie验证失败，清除认证状态
+      clearUserState()
     } finally {
       setInitializingAuth(false)
     }

src/views/HomePage.vue

@@ -182,8 +182,6 @@ const handleSignupSubmit = async () => {
       if (result.user) {
         authStore.user = result.user
         authStore.isAuthenticated = true
-        localStorage.setItem('jingrow_user', JSON.stringify(result.user))
-        localStorage.setItem('jingrow_authenticated', 'true')
         showSignupModal.value = false
         signupFormData.username = ''
         signupFormData.password = ''

src/views/auth/Signup.vue

@@ -230,8 +230,6 @@ const handleSignup = async () => {
       if (result.user) {
         authStore.user = result.user
         authStore.isAuthenticated = true
-        localStorage.setItem('jingrow_user', JSON.stringify(result.user))
-        localStorage.setItem('jingrow_authenticated', 'true')
         router.push('/')
       } else {
         const loginResult = await authStore.login(formData.username, formData.password)