chore(marketplace): remove Checkout page and route

- Remove CheckoutPage import from App.tsx
- Remove /checkout route from routing configuration

marketplace/src/App.tsx

@@ -1,7 +1,6 @@
 import { Navigate, Route, Routes } from 'react-router-dom'
 import { LoginPage } from './pages/Login'
 import { CartPage } from './pages/Cart'
-import { CheckoutPage } from './pages/Checkout'
 import { OrdersPage as UserOrdersPage } from './pages/Orders'
 import { InventoryPage } from './pages/Inventory'
 import { CompanyPage } from './pages/Company'
@@ -88,14 +87,6 @@ function App() {
           </ProtectedRoute>
         }
       />
-      <Route
-        path="/checkout"
-        element={
-          <ProtectedRoute>
-            <CheckoutPage />
-          </ProtectedRoute>
-        }
-      />
       <Route
         path="/orders"
         element={