add loader tests for absolute paths

[Mearman]

related to https://github.com/sourcepulp/transformerjs-breadboard-kit/issues/1

see: https://github.com/sourcepulp/labs-prototypes/blob/main/seeds/breadboard/tests/loader.ts

[Mearman]

based on the windows test failure. I believe absolute paths haven't been tested and when and absolute path on Windows is used, the C:/ isn't correctly interpreted as a file path see: https://github.com/sourcepulp/transformerjs-breadboard-kit/actions/runs/6718025984/job/18256948768#step:7:28

[Mearman]

Add cases for

• [ ] computed from system process.cwd()...
  • [ ] absolute path
  • [ ] relative path
• [ ] explicitly hard coded per-os file path (use CI runner to get sample values)
  • [ ] absolute path
  • [ ] relative path