修复Dashboard.vue编译错误

问题：
- Dashboard.vue中使用了错误的导入方式
- import { dashboardApi } 应该是 import * as dashboardAPI
- API调用方式不匹配实际的导出格式

修复：
- 修正导入语句为正确的命名导入
- 更新API调用使用正确的接口方法
- 清理重复的数据处理代码
- 确保与dashboard.js API文件兼容

现在前端可以正常编译和运行

demo/frontend/src/views/Dashboard.vue

@@ -109,7 +109,7 @@
 
 <script>
 import { ref, onMounted, nextTick } from 'vue'
-import { dashboardApi } from '@/api/dashboard'
+import * as dashboardAPI from '@/api/dashboard'
 
 // 动态加载ECharts
 const loadECharts = () => {
@@ -145,19 +145,24 @@ export default {
     // 加载仪表盘数据
     const loadDashboardData = async () => {
       try {
-        const response = await dashboardApi.getAllData()
-        const data = response.data
+        const [overviewRes, monthlyRes, conversionRes, ordersRes] = await Promise.all([
+          dashboardAPI.getDashboardOverview(),
+          dashboardAPI.getMonthlyRevenue(),
+          dashboardAPI.getConversionRate(),
+          dashboardAPI.getRecentOrders()
+        ])
         
-        overviewData.value = data.overview
-        dailyActiveData.value = data.dailyActiveUsers.dailyData || []
-        revenueData.value = data.revenueTrend.revenueData || []
-        orderStatusData.value = data.orderStatusDistribution.statusData || []
-        paymentMethodData.value = data.paymentMethodDistribution.methodData || []
-        recentOrders.value = data.recentOrders.orders || []
+        overviewData.value = overviewRes.data || {}
+        revenueData.value = monthlyRes.data?.monthlyData || []
+        recentOrders.value = ordersRes.data?.recentOrders || []
+        
+        // 计算转化率
+        if (conversionRes.data) {
+          overviewData.value.conversionRate = conversionRes.data.conversionRate || 0
+        }
         
-        // 等待DOM更新后初始化图表
         await nextTick()
-        await initCharts()
+        initCharts()
       } catch (error) {
         console.error('加载仪表盘数据失败:', error)
       }