forked from 1b-agent/fieldcraft-upstream
The large-deformation explicit core of #42 (objective stress rates, updated kinematics) moves the bar wave and rigid-wall impact results by a few 1e-4 relative; both still pass their references (u_end 0.034%, rebound KE -0.54%). Fixtures updated deliberately for that change. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm