Set default `user`

### Describe the feature or problem you'd like to solve

Please allow a way to set default user. I mostly use my work one but have a personal one too. Hate that it keeps defaulting to most recently added even if I use that one way less.

### Proposed solution

Helps people who balance multiple accounts but with extreme difference in usage.

### Example prompts or workflows

_No response_

### Additional context

_No response_

未指定文件、测试或入口点。首先跟踪 CLI 如何在多个已通过身份验证的用户之间进行选择，以及账户偏好设置存储或加载的位置；完成的标准是用户可以选择一个默认账户，并且该账户会保持选中状态，而不是被最近添加的账户替换。

由索引模型根据 Issue 内容生成。