feat: Display received time and fix timestamp timezone conversion.

backend/app.js

@@ -30,7 +30,7 @@ app.get('/api/messages', async (req, res) => {
 
   try {
     const [rows] = await db.execute(
-      'SELECT id, sender, recipient, subject, body, received_at FROM emails WHERE recipient LIKE ? ORDER BY received_at DESC',
+      'SELECT id, sender, recipient, subject, body, CAST(received_at AS CHAR) as received_at FROM emails WHERE recipient LIKE ? ORDER BY received_at DESC',
       [`%${recipient}%`]
     );
     res.json(rows);