dont kit::build .DS_Store

[nick1udwig]

Problem

MacOS sometimes puts .DS_Store in random places. This can break our build.rs. hyperware-ai/kit#147

Solution

Don't try to build .DS_Store, or other non-package dirs, if they exist in the packages/ dir.

Testing

cargo +nightly build -p kinode```

## Docs Update

None

## Notes

FYI @jurij-jukic