[FR] setup.sh always exiting with 1

As `conscript/setup.sh` always executes `cs` as the last thing, the script's exit status will be 1, as cs fails due to no args are passed.

I'd like to see either

- cs execution be removed from the script; or
- offer setup.sh additional flag for stand-alone execution, to skip cs invocation.

Reasoning: automated install scripts referencing setup.sh report bogus failures.

从 conscript/setup.sh 开始，不带参数运行它，以确认最后的 cs 调用会产生非零退出状态。确定所提出的两种行为中哪一种是可接受的，然后验证使用 setup.sh 的自动安装能够成功完成，且不会意外调用 cs。

由索引模型根据 Issue 内容生成。