feat: 实现 API Keys 批量删除后端功能

- 新增 DELETE /admin/api-keys/batch 端点
- 支持批量删除最多100个API Keys
- 完整的请求参数验证（数组格式、数量限制、ID有效性）
- 逐个删除并记录成功/失败状态
- 详细的错误信息和日志记录
- 返回成功/失败统计结果

请求格式: { "keyIds": ["key1", "key2", ...] }
响应格式: { "success": true, "data": { "successCount": 2, "failedCount": 0, "errors": [] } }

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.mcp.json

@@ -0,0 +1,14 @@
+{
+  "mcpServers": {
+    "spec-workflow": {
+      "type": "stdio",
+      "command": "npx",
+      "args": [
+        "-y",
+        "@pimzino/spec-workflow-mcp@latest",
+        "/Users/weidian/project/claude-relay-service"
+      ],
+      "env": {}
+    }
+  }
+}