Initial commit: lottery project structure

Add core project files including:
- Client and server directories
- Backup script
- Package configuration
- Git ignore rules

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/middleware/auth.js

@@ -0,0 +1,25 @@
+const jwt = require('jsonwebtoken');
+
+const JWT_SECRET = process.env.JWT_SECRET || 'lottery-secret-key-change-in-production';
+
+function authMiddleware(req, res, next) {
+  const token = req.headers.authorization?.split(' ')[1];
+
+  if (!token) {
+    return res.status(401).json({ error: '未登录' });
+  }
+
+  try {
+    const decoded = jwt.verify(token, JWT_SECRET);
+    req.user = decoded;
+    next();
+  } catch (err) {
+    return res.status(401).json({ error: 'token无效' });
+  }
+}
+
+function generateToken(user) {
+  return jwt.sign({ id: user.id, username: user.username }, JWT_SECRET, { expiresIn: '7d' });
+}
+
+module.exports = { authMiddleware, generateToken, JWT_SECRET };