feat: 新增 pinia 状态管理

sau_frontend/src/stores/user.js

@@ -0,0 +1,31 @@
+import { defineStore } from 'pinia'
+import { ref } from 'vue'
+
+export const useUserStore = defineStore('user', () => {
+  const userInfo = ref({
+    name: '',
+    email: ''
+  })
+  
+  const isLoggedIn = ref(false)
+  
+  const setUserInfo = (info) => {
+    userInfo.value = info
+    isLoggedIn.value = true
+  }
+  
+  const logout = () => {
+    userInfo.value = {
+      name: '',
+      email: ''
+    }
+    isLoggedIn.value = false
+  }
+  
+  return {
+    userInfo,
+    isLoggedIn,
+    setUserInfo,
+    logout
+  }
+})