fix(web): harden route transitions and monitor memory

vehicle-data-platform/apps/web/src/v2/routing/routeModules.ts

@@ -0,0 +1,47 @@
+import { lazy, type ComponentType } from 'react';
+
+export type RouteSection = 'monitor' | 'vehicles' | 'tracks' | 'history' | 'statistics' | 'access' | 'alerts' | 'operations';
+type RouteModule = { default: ComponentType };
+
+const importers: Record<RouteSection, () => Promise<RouteModule>> = {
+  monitor: () => import('../pages/MonitorPage'),
+  vehicles: () => import('../pages/VehiclePage'),
+  tracks: () => import('../pages/TrackPage'),
+  history: () => import('../pages/HistoryPage'),
+  statistics: () => import('../pages/StatisticsPage'),
+  access: () => import('../pages/AccessPage'),
+  alerts: () => import('../pages/AlertsPage'),
+  operations: () => import('../pages/OperationsPage')
+};
+
+const pendingModules = new Map<RouteSection, Promise<RouteModule>>();
+
+function loadRoute(section: RouteSection) {
+  const pending = pendingModules.get(section);
+  if (pending) return pending;
+  const next = importers[section]();
+  pendingModules.set(section, next);
+  void next.catch(() => pendingModules.delete(section));
+  return next;
+}
+
+export function routeSectionForPath(pathname: string): RouteSection | undefined {
+  const section = pathname.split('?')[0].split('#')[0].split('/').filter(Boolean)[0] as RouteSection | undefined;
+  return section && section in importers ? section : undefined;
+}
+
+export function preloadRoute(pathname: string) {
+  const section = routeSectionForPath(pathname);
+  return section ? loadRoute(section) : undefined;
+}
+
+export const RoutePages = {
+  Monitor: lazy(() => loadRoute('monitor')),
+  Vehicles: lazy(() => loadRoute('vehicles')),
+  Tracks: lazy(() => loadRoute('tracks')),
+  History: lazy(() => loadRoute('history')),
+  Statistics: lazy(() => loadRoute('statistics')),
+  Access: lazy(() => loadRoute('access')),
+  Alerts: lazy(() => loadRoute('alerts')),
+  Operations: lazy(() => loadRoute('operations'))
+} as const;