fix(login): fix back button issue

@@ -38,6 +38,7 @@ import IconFont from '@/components/icons/IconFont.vue'
  * @property {String} [background] - Custom background style (CSS value)
  * @property {String} [textColor] - Custom text/icon color (default #fff)
  * @property {Boolean} [overlay] - Whether to overlay content (no placeholder)
+ * @property {Boolean} [preventDefaultBack] - Whether to prevent default navigateBack when @back is emitted
  */
 const props = defineProps({
   title: {
@@ -59,9 +60,15 @@ const props = defineProps({
   overlay: {
     type: Boolean,
     default: false
+  },
+  preventDefaultBack: {
+    type: Boolean,
+    default: false
   }
 })
 
+const emit = defineEmits(['back'])
+
 const canGoBack = ref(false)
 
 /**
@@ -77,6 +84,14 @@ onMounted(() => {
 })
 
 const goBack = () => {
-  Taro.navigateBack()
+  // 触发 back 事件
+  // 父组件可以通过 @back 自定义返回行为
+  // 例如：登录页可以跳转到首页而非返回上一页
+  emit('back')
+
+  // 如果没有阻止默认行为，执行默认的 navigateBack
+  if (!props.preventDefaultBack) {
+    Taro.navigateBack()
+  }
 }
 </script>

 <template>
   <view class="min-h-screen bg-white flex flex-col">
     <!-- Header -->
-    <NavHeader title="" :show-back="true" />
+    <NavHeader title="" :show-back="true" :prevent-default-back="true" @back="handleBack" />
 
     <view class="flex-1 flex flex-col px-[48rpx] pt-[120rpx]">
       <!-- Logo/Title -->
@@ -80,6 +80,20 @@ const form = reactive({
 })
 
 /**
+ * Handle back button click
+ * - 清空 router store 中保存的路径
+ * - 跳转到首页（因为导航栈已被 401 清空）
+ */
+const handleBack = () => {
+  // 清空保存的路径
+  const store = routerStore()
+  store.remove()
+
+  // 跳转到首页
+  Taro.reLaunch({ url: '/pages/index/index' })
+}
+
+/**
  * Handle login action
  */
 const handleLogin = async () => {