feat(api): use dynamic import for auth headers in fetchJson function

frontend/lib/api.ts

@@ -1,5 +1,4 @@
 import { redirect } from 'next/navigation';
-import { getAuthHeaders } from './auth-headers';
 
 const API_BASE =
   process.env.NEXT_PUBLIC_API_URL_INTERNAL || 'http://recipe-api:8080';
@@ -11,7 +10,10 @@ export async function fetchJson<T>(path: string, init?: RequestInit): Promise<T>
     ? (path.startsWith('http') ? path : `${API_BASE}${path}`)
     : path;
 
-  const authHeaders = isServer ? await getAuthHeaders() : {};
+  // Dynamisk import så att auth-headers inte bundlas till klienten
+  const authHeaders = isServer
+    ? await (await import('./auth-headers')).getAuthHeaders()
+    : {};
 
   const res = await fetch(url, {
     ...init,