fix: redirect to product list after creating a product

Previously redirected to /products/{id} (edit page) which looks
identical to the create form, making it appear as if nothing happened.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/products/new/+page.server.ts

@@ -190,6 +190,6 @@ export const actions: Actions = {
 		} catch (e) {
 			return fail(500, { error: (e as Error).message });
 		}
-		redirect(303, `/products/${product.id}`);
+		redirect(303, '/products');
 	}
 };