Add rollout video (pi05 final, h25 exec)

Add rollout video (pi05 final, h25 exec)

Document step_5000 + step_7500 checkpoints

Add step-7500 checkpoint (intermediate) for overfitting comparison

Add step-5000 checkpoint (intermediate) for overfitting comparison

Document step_2500 checkpoint

Add step-2500 checkpoint (intermediate) for overfitting comparison

π₀.₅ piper_stacking BC fine-tune (10k steps, final loss 0.0012)

initial commit