use different endpoint structure

src/app/api/chat/route.js

@@ -1,7 +1,6 @@
 import { HuggingFaceInference } from "@langchain/community/llms/hf";
 
-export default async function handler(req, res) {
-  if (req.method === 'POST') {
+export async function POST(req, res) {
   try {
     const { query } = req.body;
 
@@ -17,7 +16,4 @@ export default async function handler(req, res) {
     console.error(error);
     res.status(500).json({ error: 'Error generating response' });
   }
-  } else {
-    res.status(405).json({ error: 'Method Not Allowed' });
-  }
 }