feat: M4-01 — add cost, import, task, expiration metric cards to dashboard

- Update DashboardStats type with new fields
- Add 4 new metric cards: today's AI cost, import tasks, failed tasks, upcoming expirations

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/pages/Dashboard.tsx

@@ -6,7 +6,7 @@ import * as echarts from 'echarts/core'
 import { LineChart, BarChart } from 'echarts/charts'
 import { GridComponent, TooltipComponent, TitleComponent, LegendComponent } from 'echarts/components'
 import { CanvasRenderer } from 'echarts/renderers'
-import { UserOutlined, BookOutlined, CloudOutlined, FileOutlined, ClusterOutlined } from '@ant-design/icons'
+import { UserOutlined, BookOutlined, CloudOutlined, FileOutlined, ClusterOutlined, DollarOutlined, ImportOutlined, AlertOutlined, SafetyOutlined } from '@ant-design/icons'
 import dayjs from 'dayjs'
 import MetricCard from '@/components/MetricCard'
 import { Progress, Space } from 'antd'
@@ -61,6 +61,12 @@ export default function Dashboard() {
         <Col xs={12} sm={12} lg={6}><MetricCard title="今日 AI 调用" value={stats?.totalAiCallsToday} loading={statsLoading} prefix={<CloudOutlined />} /></Col>
         <Col xs={12} sm={12} lg={6}><MetricCard title="文件存储" value={stats ? formatStorage(stats.totalStorageBytes) : undefined} loading={statsLoading} prefix={<FileOutlined />} suffix={`${stats?.totalFiles ?? 0} 个文件`} /></Col>
       </Row>
+      <Row gutter={[16, 16]} style={{ marginTop: 16 }}>
+        <Col xs={12} sm={12} lg={6}><MetricCard title="今日 AI 成本" value={stats?.todayAiCost != null ? `¥${stats.todayAiCost.toFixed(2)}` : undefined} loading={statsLoading} prefix={<DollarOutlined />} trend="up" trendValue={`${stats?.totalAiCallsToday ?? 0} 次`} trendLabel="今日调用" /></Col>
+        <Col xs={12} sm={12} lg={6}><MetricCard title="今日导入任务" value={stats?.todayImportCount ?? 0} loading={statsLoading} prefix={<ImportOutlined />} trend={stats?.failedImportCount ? 'down' : 'up'} trendValue={stats?.failedImportCount ? `${stats.failedImportCount} 失败` : '全部成功'} trendLabel="状态" /></Col>
+        <Col xs={12} sm={12} lg={6}><MetricCard title="近期失败任务" value={stats?.failedTasks ?? 0} loading={statsLoading} prefix={<AlertOutlined />} trend={stats?.failedTasks ? 'down' : 'up'} trendValue={stats?.failedTasks ? '需要关注' : '无异常'} trendLabel="7 天内" /></Col>
+        <Col xs={12} sm={12} lg={6}><MetricCard title="即将到期密钥" value={stats?.upcomingExpirations ?? 0} loading={statsLoading} prefix={<SafetyOutlined />} trend={stats?.upcomingExpirations ? 'down' : 'up'} trendValue="30 天内" trendLabel="到期" /></Col>
+      </Row>
       <Row gutter={[16, 16]} style={{ marginTop: 16 }}>
         <Col xs={24} lg={12}><EChartsChartContainer title="日活用户趋势（近 30 天）" loading={statsLoading} isEmpty={!stats?.userTrend?.length}><ReactEChartsCore echarts={echarts} option={userTrendOption} style={{ height: 300 }} notMerge lazyUpdate /></EChartsChartContainer></Col>
         <Col xs={24} lg={12}><EChartsChartContainer title="AI 调用趋势（近 30 天）" loading={statsLoading} isEmpty={!stats?.aiCallTrend?.length}><ReactEChartsCore echarts={echarts} option={aiCallTrendOption} style={{ height: 300 }} notMerge /></EChartsChartContainer></Col>

src/types/admin.ts

@@ -26,6 +26,11 @@ export interface DashboardStats {
   totalAiCallsToday: number
   totalFiles: number
   totalStorageBytes: number
+  todayImportCount: number
+  failedImportCount: number
+  todayAiCost: number
+  failedTasks: number
+  upcomingExpirations: number
   userTrend: TrendPoint[]
   aiCallTrend: TrendPoint[]
 }