Merge Initial Anatomical Preprocessing PR

[nx10]

Merge PR with anatomical reorientation, brain extraction, and registration.

• Remove files from LFS and commit them directly (they are much smaller than the 100MB limit)
• Address review comments
• Add unit tests for utilities
• Add integration test (or mark as slow)
• Merge PR

The PR includes reorient(), ants_brain_extraction(), ants_registration(), and utility functions.

Note: Brain extraction and registration are slow - mark with @pytest.mark.full_pipeline