[Feature] 工作流中添加自定义命令

### 功能描述 / Description

希望在工作流中添加单独的命令执行

### 请求动机 / Motivation

如部署多个独立域名证书，最后统一重启nginx，或者可以shell处理一些其他的工作

### 其他 / Miscellaneous

_No response_

### 贡献 / Contribution

- [ ] 我乐意为此贡献代码！ / I am interested in contributing to this feature!

The issue names no files, tests, or entry points. First locate the workflow execution path and determine how a standalone custom command would fit alongside existing steps; done means a workflow can run the requested command for cases such as restarting nginx, with the behavior defined clearly enough to test.

Written by the indexing model from the issue text.