feat: implement import functionality with tab navigation for receipts and invoices

frontend/app/kvitto/page.tsx

@@ -1,16 +1,5 @@
-import Navigation from '../Navigation';
-import ReceiptImportClient from './ReceiptImportClient';
+import { redirect } from 'next/navigation';
 
 export default function KvittoPage() {
-  return (
-    <main style={{ padding: '1rem', maxWidth: '700px', margin: '0 auto' }}>
-      <Navigation />
-      <h1 style={{ marginBottom: '0.25rem' }}>Importera kvitto</h1>
-      <p style={{ color: '#666', marginBottom: '1.5rem' }}>
-        Fotografera eller ladda upp ett kvitto — varorna läggs till i ditt
-        inventarie.
-      </p>
-      <ReceiptImportClient />
-    </main>
-  );
+  redirect('/import?tab=kvitto');
 }