feat(library): Steam wishlist tab with prices and discounts

The library page gets a Bibliothek | Wunschliste tab bar. The wishlist shows
the current store price, the discount and can show only games on sale.

src/App.jsx

@@ -10,6 +10,7 @@ import RegistrationPage from './pages/RegistrationPage.jsx';
 import SettingsPage from './pages/SettingsPage.jsx';
 import GameLibrary from './pages/GameLibrary.jsx';
 import GameDetail from './pages/GameDetail.jsx';
+import WishlistPage from './pages/WishlistPage.jsx';
 import AppHeader from './components/AppHeader.jsx';
 import {Toaster} from '@/components/ui/sonner';
 import {TooltipProvider} from '@/components/ui/tooltip';
@@ -47,6 +48,7 @@ function App() {
                         <Route path="/dashboard" element={<Dashboard/>}/>
                         <Route path="/library" element={<GameLibrary/>}/>
                         <Route path="/library/:appid" element={<GameDetail/>}/>
+                        <Route path="/wishlist" element={<WishlistPage/>}/>
                         <Route path="/settings" element={<SettingsPage/>}/>
                         <Route path="/impressum" element={<ImprintPage/>}/>
                     </Routes>