refactor: Dashboard 看板布局与图表优化

DashboardView 调整看板卡片与栅格展示，ECharts 补充图表类型，主布局 dashboard 区域由内嵌滚动改为自适应可滚动以避免内容被裁剪，回归脚本适配。

frontend/src/plugins/echarts.ts

@@ -4,7 +4,7 @@
  */
 import { use } from 'echarts/core'
 import { CanvasRenderer } from 'echarts/renderers'
-import { BarChart, LineChart } from 'echarts/charts'
+import { BarChart, LineChart, PieChart } from 'echarts/charts'
 import {
   GridComponent,
   TooltipComponent,
@@ -17,6 +17,7 @@ use([
   CanvasRenderer,
   BarChart,
   LineChart,
+  PieChart,
   GridComponent,
   TooltipComponent,
   LegendComponent,