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 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm
