add route matcher to fix /login and /logout routes

Use SvelteKit param matcher to constrain [recipeLang] to only match
'recipes' or 'rezepte', preventing it from catching /login, /logout,
and other non-recipe routes.

src/routes/[recipeLang=recipeLang]/favorites/+page.server.ts

@@ -0,0 +1,34 @@
+import type { PageServerLoad } from "./$types";
+import { redirect } from '@sveltejs/kit';
+
+export const load: PageServerLoad = async ({ fetch, locals, params }) => {
+    const isEnglish = params.recipeLang === 'recipes';
+    const apiBase = isEnglish ? '/api/recipes' : '/api/rezepte';
+    const session = await locals.auth();
+
+    if (!session?.user?.nickname) {
+        throw redirect(302, `/${params.recipeLang}`);
+    }
+
+    try {
+        const res = await fetch(`${apiBase}/favorites/recipes`);
+        if (!res.ok) {
+            return {
+                favorites: [],
+                error: 'Failed to load favorites'
+            };
+        }
+
+        const favorites = await res.json();
+
+        return {
+            favorites,
+            session
+        };
+    } catch (e) {
+        return {
+            favorites: [],
+            error: 'Failed to load favorites'
+        };
+    }
+};