Add a callable function to run DetectGPT without CLI

Hi, thanks for the great work on this repo!
Would it be possible to:
- Expose the main logic from run.py as a callable Python function, or
- Point to an existing function that allows running DetectGPT programmatically (i.e., without going through the CLI)?

This would make it easier to use DetectGPT as a library from within other Python scripts or notebooks.
Thanks in advance!