refactor: use user_servers junction table instead of JSON column

backend/routes/users.js

@@ -6,15 +6,20 @@ const { authenticate, requireRole } = require('../middleware/auth');
 const router = express.Router();
 
 router.get('/', authenticate, requireRole('owner','admin'), async (req, res) => {
-  res.json(await query('SELECT id, username, email, game_name, game_uid, source, role, active, admin_servers, email_verified, created_at FROM users ORDER BY created_at DESC'));
+  res.json(await query('SELECT id, username, email, game_name, game_uid, source, role, active, email_verified, created_at FROM users ORDER BY created_at DESC'));
 });
 
 router.get('/:id', authenticate, requireRole('owner','admin'), async (req, res) => {
   const u = await getRow('SELECT id, username, email, game_name, game_uid, source, role, active, email_verified, created_at FROM users WHERE id = ?', [req.params.id]);
   if (!u) return res.status(404).json({ error: '用户不存在' });
+  u.servers = await query('SELECT group_name, server_name FROM user_servers WHERE user_id = ?', [req.params.id]);
   res.json(u);
 });
 
+router.get('/:id/servers', authenticate, requireRole('owner','admin'), async (req, res) => {
+  res.json(await query('SELECT group_name, server_name FROM user_servers WHERE user_id = ?', [req.params.id]));
+});
+
 router.post('/', authenticate, requireRole('owner','admin'), async (req, res) => {
   const { username, password, email, game_name, game_uid, role, source } = req.body;
   if (!username||!password||!email||!game_name||!game_uid||!role) return res.status(400).json({ error: '所有字段必填' });
@@ -43,6 +48,18 @@ router.put('/:id', authenticate, requireRole('owner','admin'), async (req, res)
   if (!Object.keys(fields).length) return res.status(400).json({ error: '无更新内容' });
   const sets = Object.keys(fields).map(k => `${k} = ?`).join(', ');
   await query(`UPDATE users SET ${sets} WHERE id = ?`, [...Object.values(fields), req.params.id]);
+
+  if (req.body.admin_servers !== undefined) {
+    await query('DELETE FROM user_servers WHERE user_id = ?', [req.params.id]);
+    if (Array.isArray(req.body.admin_servers)) {
+      for (const s of req.body.admin_servers) {
+        if (s.group_name && s.server_name) {
+          await query('INSERT IGNORE INTO user_servers(user_id, group_name, server_name) VALUES (?,?,?)', [req.params.id, s.group_name, s.server_name]);
+        }
+      }
+    }
+  }
+
   await query("INSERT INTO audit_logs(user_id, username, action, entity_type, entity_id, details) VALUES (?,?,?,?,?,?)", [req.user.id, req.user.username, 'update_user', 'user', req.params.id, '更新用户']);
   res.json({ message: '更新成功' });
 });