feat: 完成布局/仪表板/用户相关组件国际化与语言切换优化（TabBar/MainLayout/AppHeader、UsageTrend/ModelDistribution、User*、Common 组件、i18n/locale 增强）

web/admin-spa/src/components/common/ToastNotification.vue

@@ -12,8 +12,8 @@
             <i :class="getIconClass(toast.type)" />
           </div>
           <div class="toast-body">
-            <div v-if="toast.title" class="toast-title">
-              {{ toast.title }}
+            <div v-if="toast.title || getDefaultTitle(toast.type)" class="toast-title">
+              {{ toast.title || getDefaultTitle(toast.type) }}
             </div>
             <div class="toast-message">
               {{ toast.message }}
@@ -35,6 +35,9 @@
 
 <script setup>
 import { ref, onMounted, onUnmounted } from 'vue'
+import { useI18n } from 'vue-i18n'
+
+const { t } = useI18n()
 
 // 状态
 const toasts = ref([])
@@ -51,6 +54,11 @@ const getIconClass = (type) => {
   return iconMap[type] || iconMap.info
 }
 
+// 获取默认标题
+const getDefaultTitle = (type) => {
+  return t(`common.toastNotification.defaultTitles.${type}`)
+}
+
 // 添加Toast
 const addToast = (message, type = 'info', title = null, duration = 5000) => {
   const id = ++toastIdCounter