Working directory inference from '.Rproj' files

I apologize in advance if this issue has been asked/closed/addressed! I couldn't find it in the issues tab or the wiki.

Is your feature request related to a problem? Please describe.
It's not a huge problem, but it would be nice to have an option making the generated R session (e.g. when a piece of R code is run through 'R: Run Comnand in Terminal') be created with the working directory set to the R project that the code was written in. This would match the paradigm of R projects and offer support similar to that of RStudio

For example, in a VSCode workspace resembling:

- top-level-folder
    - my-r-project  
        - my-r-project.Rproj
        - script-1.R
    - a-different-folder
        - script-2.R
        - a-different-project.Rproj

If code from script-1.R was run, it would be nice for it to be run relative to my-r-project, rather than top-level-folder (as is the current behavior).

Describe the solution you'd like

An option called r.workingdirectory, with possible values being

• workspace: uses the highest folder in the VSCode workspace that the code was run in, I believe this matches the default behavior
• Rproj: beginning from the directory of the file, looks for a .Rproj file; if it sees one, it uses that directory, if it doesn't, it looks one directory higher and repeats until either R_HOME or '/' is reached
• file: uses the directory that this file is contained in, without looking any higher

Describe alternatives you've considered

The alternative and current strategy is to simply run setwd() when the working directory does not match what is desired, which is still not that bad.

Edit: I've found another alternative is to edit '~/.vscode-R/init.R', which could serve as a per-user workaround. I think a dedicated option would still be best, but yep!

Start by tracing the R: Run Command in Terminal command and how it selects the working directory. Review the proposed r.workingdirectory values and the .Rproj search behavior in the issue. Done means each option uses the specified directory, including fallback behavior when no .Rproj file is found.