Start on new sidebar (#456)

Co-authored-by: shadcn <m@shadcn.com>

app/(chat)/actions.ts

@@ -0,0 +1,8 @@
+'use server';
+
+import { cookies } from 'next/headers';
+
+export async function saveModel(model: string) {
+  const cookieStore = await cookies();
+  cookieStore.set('model', model);
+}