feat: Add expandable section for creating products with integrated product form

frontend/app/admin/products/page.tsx

@@ -3,6 +3,7 @@ import type { Product } from '../../../features/inventory/types';
 import MergePreviewForm from './MergePreviewForm';
 import AdminProductList from './AdminProductList';
 import Navigation from '../../Navigation';
+import ExpandableCreateProductSection from './ExpandableCreateProductSection';
 
 export default async function AdminProductsPage() {
   const products = await fetchJson<Product[]>('/api/products');
@@ -13,6 +14,8 @@ export default async function AdminProductsPage() {
       <h1 style={{ marginBottom: '1.5rem' }}>Admin: Produkter</h1>
       <p>Här kan du granska och standardisera produktnamn.</p>
 
+      <ExpandableCreateProductSection />
+
       <MergePreviewForm products={products} />
 
       <AdminProductList products={products} />