Conformal Prediction Wrappers

[soulios-basf]

Overview:
This PR introduces several new files to support conformal prediction in molecular machine learning pipelines, as well as comprehensive unit tests for pipeline and conformal prediction functionality.

conformal.py: Implements UnifiedConformalCV(single-model) and CrossConformalCV(aggregate CP) wrappers for easy conformal prediction (classification/regression) on top of scikit-learn models.
test_conformal.py: Unit tests for the conformal wrappers, covering both regression and classification.
test_pipeline.py: Unit tests for the main pipeline, including integration with conformal prediction.
advanced_04_conformal_prediction.ipynb: Example notebook showing conformal prediction on molecular data, with benchmarking and visualization.

How to test:
Run pytest on the new test files to verify correctness.
Open and run all cells in the notebook to see conformal prediction in action.

[JochenSiegWork]

This is the first part of my review. I mainly looked at conformal.py and only shortly on the test.