perf(web): reuse locale formatters

vehicle-data-platform/apps/web/src/v2/pages/StatisticsPage.tsx

@@ -5,6 +5,7 @@ import { useSearchParams } from 'react-router-dom';
 import { api } from '../../api/client';
 import type { DailyMileageRow, MileageStatistics, Page, VehicleRow } from '../../api/types';
 import { downloadMileageWorkbook } from '../domain/mileageExport';
+import { formatZhNumber } from '../domain/formatters';
 import { InlineError } from '../shared/AsyncState';
 import { QUERY_MEMORY, retainPreviousPageWithinScope } from '../queryPolicy';
 
@@ -41,7 +42,7 @@ function defaultWindow(days = 30) {
 
 function formatKm(value?: number) {
   if (value == null || !Number.isFinite(value)) return '—';
-  return new Intl.NumberFormat('zh-CN', { maximumFractionDigits: 1 }).format(value);
+  return formatZhNumber(value, 1);
 }
 
 function inclusiveDays(dateFrom: string, dateTo: string) {