add create user and login user parts

app/utils/jwt.util.js

@@ -15,6 +15,9 @@ require("dotenv").config();
 const JWT_SECRET = process.env.JWT_SECRET || "your_jwt_secret_key";
 const JWT_EXPIRES_IN = process.env.JWT_EXPIRES_IN || "1d"; // token validity
 
+const REFRESH_TOKEN_SECRET = process.env.REFRESH_TOKEN_SECRET || "your_refresh_token_secret_key";
+const REFRESH_TOKEN_DAYS = process.env.REFRESH_TOKEN_DAYS || "7d"; // refresh token validity
+
 /**
  * Generate JWT token
  * @param {Object} payload - usually { id, email, role }
@@ -33,4 +36,12 @@ const verifyToken = (token) => {
   return jwt.verify(token, JWT_SECRET);
 };
 
-module.exports = { generateToken, verifyToken };
+const generateRefreshToken = (payload) => {
+  return jwt.sign(payload, REFRESH_TOKEN_SECRET, { expiresIn: REFRESH_TOKEN_DAYS });
+}
+
+const verifyRefreshToken = (token) => {
+  return jwt.verify(token, REFRESH_TOKEN_SECRET);
+}
+
+module.exports = { generateToken, verifyToken, generateRefreshToken, verifyRefreshToken };