feat: 添加API Key并发控制和编辑功能

- 新增API Key并发控制功能
  - 创建API Key时可设置并发限制（0为不限制）
  - 在认证中间件中实现并发检查
  - 使用Redis原子操作确保计数准确
  - 添加自动清理机制处理异常情况

- 新增API Key编辑功能
  - 支持修改Token限制和并发限制
  - 前端添加编辑按钮和模态框
  - 后端限制只能修改指定字段

- 其他改进
  - 添加test-concurrency.js测试脚本
  - 添加详细的功能说明文档
  - 所有代码通过ESLint检查

🤖 Generated with Claude Code

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

src/routes/admin.js

@@ -32,7 +32,8 @@ router.post('/api-keys', authenticateAdmin, async (req, res) => {
       tokenLimit,
       requestLimit,
       expiresAt,
-      claudeAccountId
+      claudeAccountId,
+      concurrencyLimit
     } = req.body;
 
     // 输入验证
@@ -56,13 +57,18 @@ router.post('/api-keys', authenticateAdmin, async (req, res) => {
       return res.status(400).json({ error: 'Request limit must be a non-negative integer' });
     }
 
+    if (concurrencyLimit !== undefined && concurrencyLimit !== null && concurrencyLimit !== '' && (!Number.isInteger(Number(concurrencyLimit)) || Number(concurrencyLimit) < 0)) {
+      return res.status(400).json({ error: 'Concurrency limit must be a non-negative integer' });
+    }
+
     const newKey = await apiKeyService.generateApiKey({
       name,
       description,
       tokenLimit,
       requestLimit,
       expiresAt,
-      claudeAccountId
+      claudeAccountId,
+      concurrencyLimit
     });
 
     logger.success(`🔑 Admin created new API key: ${name}`);
@@ -77,7 +83,24 @@ router.post('/api-keys', authenticateAdmin, async (req, res) => {
 router.put('/api-keys/:keyId', authenticateAdmin, async (req, res) => {
   try {
     const { keyId } = req.params;
-    const updates = req.body;
+    const { tokenLimit, concurrencyLimit } = req.body;
+
+    // 只允许更新tokenLimit和concurrencyLimit
+    const updates = {};
+    
+    if (tokenLimit !== undefined && tokenLimit !== null && tokenLimit !== '') {
+      if (!Number.isInteger(Number(tokenLimit)) || Number(tokenLimit) < 0) {
+        return res.status(400).json({ error: 'Token limit must be a non-negative integer' });
+      }
+      updates.tokenLimit = Number(tokenLimit);
+    }
+
+    if (concurrencyLimit !== undefined && concurrencyLimit !== null && concurrencyLimit !== '') {
+      if (!Number.isInteger(Number(concurrencyLimit)) || Number(concurrencyLimit) < 0) {
+        return res.status(400).json({ error: 'Concurrency limit must be a non-negative integer' });
+      }
+      updates.concurrencyLimit = Number(concurrencyLimit);
+    }
 
     await apiKeyService.updateApiKey(keyId, updates);