refactor(web-app): migrate to TypeScript, add security fix and test suite

web-app/src/utils/testUtils.tsx

@@ -0,0 +1,25 @@
+import React from 'react';
+import { render, RenderOptions } from '@testing-library/react';
+import { BrowserRouter } from 'react-router-dom';
+
+// Custom render with router
+interface CustomRenderOptions extends Omit<RenderOptions, 'wrapper'> {
+  route?: string;
+}
+
+export function renderWithRouter(
+  ui: React.ReactElement,
+  { route = '/', ...renderOptions }: CustomRenderOptions = {}
+): ReturnType<typeof render> {
+  window.history.pushState({}, 'Test page', route);
+
+  return render(ui, {
+    wrapper: ({ children }) => (
+      <BrowserRouter>{children}</BrowserRouter>
+    ),
+    ...renderOptions,
+  });
+}
+
+// Re-export everything from testing-library
+export * from '@testing-library/react';