feat(monitor): preserve investigation context

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

@@ -3,6 +3,7 @@ import { cleanup, fireEvent, render, screen, waitFor } from '@testing-library/re
 import { afterEach, expect, test, vi } from 'vitest';
 import { MemoryRouter } from 'react-router-dom';
 import StatisticsPage from './StatisticsPage';
+import { buildMonitorPath, withMonitorReturn } from '../routing/monitorContext';
 import { ROUTER_FUTURE } from '../routing/routerConfig';
 
 const mocks = vi.hoisted(() => ({ mileageStatistics: vi.fn(), dailyMileage: vi.fn(), vehicles: vi.fn(), vehicleCoverage: vi.fn() }));
@@ -85,6 +86,20 @@ test('defaults to seven days and supports today and yesterday shortcuts', async
   });
 });
 
+test('preserves the exact monitor return after a mileage date shortcut', async () => {
+  prepareData();
+  const monitorPath = buildMonitorPath({
+    mode: 'list', keyword: '', protocol: '', status: '', selectedVin: 'LTEST000000000001', detailOpen: false,
+    viewport: { zoom: 5, bounds: '' }, listOffset: 40, listLimit: 20, hasViewport: false
+  });
+  renderPage(withMonitorReturn('/statistics?vins=LTEST000000000001&dateFrom=2026-07-13&dateTo=2026-07-14', monitorPath));
+
+  expect(await screen.findByRole('link', { name: /返回全局监控/ })).toHaveAttribute('href', monitorPath);
+  fireEvent.click(screen.getByRole('button', { name: '今天' }));
+
+  expect(await screen.findByRole('link', { name: /返回全局监控/ })).toHaveAttribute('href', monitorPath);
+});
+
 test('rejects overlong mileage ranges before querying or rendering a huge matrix', async () => {
   prepareData();
   const view = renderPage('/statistics?vins=LTEST000000000001&dateFrom=2025-01-01&dateTo=2026-07-14');