2.2.4.3 Middleware (JWT Authentication)

// src/middleware/auth.js
const jwt = require('jsonwebtoken');

module.exports = async (req, res, next) => {
  const header = req.headers.authorization || '';
  const token = header.replace('Bearer ', '');
  if (!token) return res.status(401).json({ error: 'No token provided' });

  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET);
    req.user = decoded; // attach user info to request
    next();
  } catch (err) {
    return res.status(403).json({ error: 'Invalid token' });
  }
};