Fix runtime error

src/App.js

@@ -70,9 +70,12 @@ const PrivateRoute = ({ children, adminOnly = false }) => {
 };
 
 function App() {
+  // Use /membership basename only in production
+  const basename = process.env.NODE_ENV === 'production' ? '/membership' : '';
+
   return (
     <AuthProvider>
-      <BrowserRouter basename="/membership">
+      <BrowserRouter basename={basename}>
         <Routes>
           <Route path="/" element={<Landing />} />
           <Route path="/register" element={<Register />} />