forked from 1b-agent/fieldcraft-upstream
Parked work for #182/#185 (not for merge as is): - contact: held active set with primal-dual updates replaces the inconsistent ENGAGED_BAND tangent after chattering (moves the nl-friction-sliding-blocks fixture by 4.5e-8; not re-blessed) - nonlinear: opt-in viscous stabilization (step 'stabilization', calibrated on the first increment), Abaqus STABILIZE, LS-DYNA refusal - ordering: graph (level-structure) nested dissection, chosen when it fills less: half the fill on the revolved boot, factor time 62 s -> 25 s - engine: mesh.revolve command (2D profile -> hex8/wedge6, tags kept) - engine: sample/boot.rs boot-seal profile, axisymmetric and 3D scripts Scratch still in the code: FC_TRACE/TIMES timing prints, NO_BAND/STAB/ SQUEEZE env hooks in tests, boot_axisymmetric_scratch test. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo