feat(ui): wishlist page, recipe toggle button, header link

- /wishlist renders cards with avatar-badge of who added it, like count,
  heart toggle for active profile, delete button. Sort dropdown switches
  between popular / newest / oldest.
- /recipes/[id] gets 'Auf Wunschliste (setzen)' button alongside favorite.
- Layout header shows 🍽️ link to /wishlist next to the admin ⚙️.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/routes/+layout.svelte

@@ -13,7 +13,8 @@
 <header class="bar">
   <a href="/" class="brand">Kochwas</a>
   <div class="bar-right">
-    <a href="/admin" class="admin-link" aria-label="Einstellungen">⚙️</a>
+    <a href="/wishlist" class="nav-link" aria-label="Wunschliste">🍽️</a>
+    <a href="/admin" class="nav-link" aria-label="Einstellungen">⚙️</a>
     <ProfileSwitcher />
   </div>
 </header>
@@ -59,7 +60,7 @@
     align-items: center;
     gap: 0.5rem;
   }
-  .admin-link {
+  .nav-link {
     display: inline-flex;
     align-items: center;
     justify-content: center;
@@ -69,7 +70,7 @@
     text-decoration: none;
     font-size: 1.15rem;
   }
-  .admin-link:hover {
+  .nav-link:hover {
     background: #f4f8f5;
   }
   main {