Refactor UI modules and harden run/API behavior

ui/src/App.tsx

@@ -0,0 +1,22 @@
+
+import { BrowserRouter, Routes, Route } from 'react-router-dom';
+import MainLayout from './layouts/MainLayout';
+import Dashboard from './pages/Dashboard';
+import Settings from './pages/Settings';
+import History from './pages/History';
+
+function App() {
+  return (
+    <BrowserRouter>
+      <Routes>
+        <Route path="/" element={<MainLayout />}>
+          <Route index element={<Dashboard />} />
+          <Route path="history" element={<History />} />
+          <Route path="settings" element={<Settings />} />
+        </Route>
+      </Routes>
+    </BrowserRouter>
+  );
+}
+
+export default App;