QTZPOC-13: Introduce joblib fallback for MLflow model loading
Enhances model loading resilience by attempting to deserialize models directly with joblib if MLflow's native flavor loaders fail. This mechanism handles cases where .pkl files are present in the artifact.
Adds joblib as a core dependency and includes new end-to-end and unit tests to validate fallback behavior, covering success, no-fallback, and double-failure scenarios. Also updates .gitignore for .claude/ files and incorporates minor refactorings and linting adjustments across E2E tests and utility functions.
Enhance E2E testing with MinIO support and update documentation
- Updated `requirements-dev.txt` to include MinIO support in testcontainers.
- Added a new fixture for MinIO container setup in `conftest.py` to facilitate E2E tests involving S3-compatible storage.
- Introduced a new test fixture for activities using a real MinIO container in `conftest.py`.
- Updated E2E test scenarios and documentation to reflect the integration of MinIO for offload uploads and clarified error handling in workflows.
- Refactored existing tests to improve clarity and maintainability.
