19b1ef125b
Adds a second ntuple alongside the existing "Hits" ntuple with one row per Geant4 step. Records event_id, track_id, step_no, PDG code, and pre/post position + kinetic energy for every step in the simulation. Also extends run_batch() with return_steps=False; when True, returns (hits_mf, steps_mf) instead of just hits_mf. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>