fix(process-directory): Add ability to pass custom working directory to ProcessRunner

[franklinfollis]

Summary

Adds a workingDirectory parameter to ProcessShell.ProcessOptions. Allows for specifying what directory a process is going to be run in.

When workingDirectory isn't specified when creating a sub process, we default to the current directory (Path.of(System.getProperty("user.dir")))

Specifically wanted this for stringToTask in SubprocessRunner to be able to create a sub process for the server project in db studio:

stringToTask("elide run", workingDirectory = Path.of(".dev/db-studio/api"))