feat: implement frontend Web UI pages

- Add types for all API models (MealPlan, Recipe, Ingredient, etc.)
- Add API client with mealPlannerApi wrapper for all endpoints
- Implement Dashboard with weekly meal plan grid view
- Implement Pantry page with add/remove functionality
- Implement MealDetail page with recipe display
- Implement ShoppingList page with aisle grouping
- Add ShoppingList route to App.tsx
- Add vite-env.d.ts for Vite env type support

frontend/src/App.tsx

@@ -3,6 +3,7 @@ import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import Dashboard from './pages/Dashboard'
 import MealDetail from './pages/MealDetail'
 import Pantry from './pages/Pantry'
+import ShoppingList from './pages/ShoppingList'
 
 const queryClient = new QueryClient()
 
@@ -21,6 +22,9 @@ function App() {
                   <Link to="/pantry" className="inline-flex items-center px-1 pt-1 text-sm font-medium text-gray-500 hover:text-gray-900">
                     Pantry
                   </Link>
+                  <Link to="/shopping-list" className="inline-flex items-center px-1 pt-1 text-sm font-medium text-gray-500 hover:text-gray-900">
+                    Shopping List
+                  </Link>
                 </div>
               </div>
             </div>
@@ -30,6 +34,7 @@ function App() {
               <Route path="/" element={<Dashboard />} />
               <Route path="/meals/:id" element={<MealDetail />} />
               <Route path="/pantry" element={<Pantry />} />
+              <Route path="/shopping-list" element={<ShoppingList />} />
             </Routes>
           </main>
         </div>