fix(web): harden route transitions and monitor memory

vehicle-data-platform/apps/web/src/v2/hooks/useMonitorData.cache.test.tsx

@@ -0,0 +1,35 @@
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { cleanup, renderHook, waitFor } from '@testing-library/react';
+import { afterEach, expect, test, vi } from 'vitest';
+import type { ReactNode } from 'react';
+import { api } from '../../api/client';
+import { useMonitorData } from './useMonitorData';
+
+afterEach(() => {
+  cleanup();
+  vi.restoreAllMocks();
+});
+
+test('rapid viewport changes retain at most one monitor map payload', async () => {
+  vi.spyOn(api, 'monitorSummary').mockResolvedValue({ totalVehicles: 0, onlineVehicles: 0, offlineVehicles: 0, drivingVehicles: 0, idleVehicles: 0, unknownVehicles: 0, alertVehicles: 0, activeToday: 0, frameToday: 0, alertDataAvailable: false, truncated: false, asOf: '' });
+  const monitorMap = vi.spyOn(api, 'monitorMap').mockResolvedValue({ mode: 'points', zoom: 13, total: 0, truncated: false, points: [], clusters: [], asOf: '' });
+  const client = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+  const wrapper = ({ children }: { children: ReactNode }) => <QueryClientProvider client={client}>{children}</QueryClientProvider>;
+  const filters = { keyword: '', protocol: '', status: '' };
+  const view = renderHook(({ bounds }) => useMonitorData(filters, { zoom: 13, bounds }, '', true, false), {
+    wrapper,
+    initialProps: { bounds: '113.0000,22.0000,114.0000,23.0000' }
+  });
+
+  await waitFor(() => expect(monitorMap).toHaveBeenCalledTimes(1));
+  for (let index = 1; index <= 8; index += 1) {
+    view.rerender({ bounds: `${113 + index / 1000},22,${114 + index / 1000},23` });
+    await waitFor(() => expect(monitorMap.mock.calls.length).toBeGreaterThanOrEqual(index + 1));
+  }
+  await waitFor(() => {
+    const cachedMaps = client.getQueryCache().findAll({ queryKey: ['monitor', 'map'] });
+    expect(cachedMaps).toHaveLength(1);
+  });
+  view.unmount();
+  client.clear();
+});