Fix NextAuth v4 imports and exports

app/api/lists/[id]/last-updated/route.ts

@@ -1,6 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server'
 import { prisma } from '@/lib/db'
-import { auth } from '@/auth'
+import { getServerSession } from 'next-auth'
+import { authOptions } from '@/pages/api/auth/[...nextauth]'
 
 export const dynamic = 'force-dynamic'
 export const revalidate = 0
@@ -10,7 +11,7 @@ export async function GET(
   { params }: { params: { id: string } }
 ) {
   try {
-    const session = await auth()
+    const session = await getServerSession(authOptions)
     if (!session?.user?.id) {
       return NextResponse.json(
         { error: 'Unauthorized' },