fix: use dynamic recipeLang in API calls instead of hardcoded /api/rezepte

Client-side navigation to /recipes hung because getUserFavorites and
other endpoints were hardcoded to /api/rezepte, causing fetch mismatches
during SvelteKit's client-side routing.

src/lib/components/FavoriteButton.svelte

@@ -1,9 +1,12 @@
 <script lang="ts">
   import { browser } from '$app/environment';
   import { enhance } from '$app/forms';
+  import { page } from '$app/stores';
 
   let { recipeId, isFavorite = $bindable(false), isLoggedIn = false } = $props<{ recipeId: string, isFavorite?: boolean, isLoggedIn?: boolean }>();
 
+  const recipeLang = $derived($page.url.pathname.split('/')[1] || 'rezepte');
+
   let isLoading = $state(false);
 
   async function toggleFavorite(event: Event) {
@@ -17,7 +20,7 @@
       
       try {
         const method = isFavorite ? 'DELETE' : 'POST';
-        const response = await fetch('/api/rezepte/favorites', {
+        const response = await fetch(`/api/${recipeLang}/favorites`, {
           method,
           headers: {
             'Content-Type': 'application/json',

src/lib/components/recipes/Search.svelte

@@ -284,7 +284,7 @@
                 const apiBase = `/api/${isEnglish ? 'recipes' : 'rezepte'}`;
                 const [tagsRes, iconsRes] = await Promise.all([
                     fetch(`${apiBase}/items/tag`),
-                    fetch('/api/rezepte/items/icon')
+                    fetch(`${apiBase}/items/icon`)
                 ]);
                 availableTags = await tagsRes.json();
                 availableIcons = await iconsRes.json();

src/lib/server/favorites.ts

@@ -7,7 +7,7 @@ import type { Session } from '@auth/sveltekit';
 
 type BriefRecipeWithFavorite = BriefRecipeType & { isFavorite: boolean };
 
-export async function getUserFavorites(fetch: typeof globalThis.fetch, locals: App.Locals): Promise<string[]> {
+export async function getUserFavorites(fetch: typeof globalThis.fetch, locals: App.Locals, recipeLang = 'rezepte'): Promise<string[]> {
     const session = await locals.auth();
 
     if (!session?.user?.nickname) {
@@ -15,7 +15,7 @@ export async function getUserFavorites(fetch: typeof globalThis.fetch, locals: A
     }
 
     try {
-        const favRes = await fetch('/api/rezepte/favorites');
+        const favRes = await fetch(`/api/${recipeLang}/favorites`);
         if (favRes.ok) {
             const favData = await favRes.json();
             return favData.favorites || [];
@@ -44,11 +44,12 @@ export function addFavoriteStatusToRecipes(recipes: BriefRecipeType[], userFavor
 export async function loadRecipesWithFavorites(
     fetch: typeof globalThis.fetch,
     locals: App.Locals,
-    recipeLoader: () => Promise<BriefRecipeType[]>
+    recipeLoader: () => Promise<BriefRecipeType[]>,
+    recipeLang = 'rezepte'
 ): Promise<{ recipes: BriefRecipeWithFavorite[], session: Session | null }> {
     const [recipes, userFavorites, session] = await Promise.all([
         recipeLoader(),
-        getUserFavorites(fetch, locals),
+        getUserFavorites(fetch, locals, recipeLang),
         locals.auth()
     ]);