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/pages/GameLibrary.jsx

@@ -16,6 +16,7 @@ import {Input} from '@/components/ui/input';
 import {Select, SelectContent, SelectItem, SelectTrigger, SelectValue} from '@/components/ui/select';
 import {Skeleton} from '@/components/ui/skeleton';
 import GameCover from '../components/GameCover.jsx';
+import LibraryTabs from '../components/LibraryTabs.jsx';
 import GameStatusBadge from '../components/GameStatusBadge.jsx';
 
 const PAGE_SIZES = [20, 40, 80];
@@ -145,6 +146,7 @@ export default function GameLibrary() {
         <div className="w-full max-w-5xl mx-auto p-4 md:p-8 space-y-6">
             <div className="flex flex-col gap-4 md:flex-row md:items-end md:justify-between">
                 <div className="space-y-2">
+                    <LibraryTabs/>
                     <h1 className="text-3xl font-bold tracking-tight">{t('LIBRARY.TITLE')}</h1>
                     <div className="flex flex-wrap items-center gap-3">
                         <SyncStatusBadge