ABI 2. One body descriptor replaces add_sphere/add_static_box (kinds: sphere, capsule, box, static box).
Revolute, spherical and weld joints created from a world anchor and axis, with joint state lanes (angle,
frame A orientation, relative rotation, relative angular velocity). Per-body force and torque write lanes,
applied before the step then cleared; non-finite values refuse the step. Parent and limb index lanes.
Tests run serially: concurrent b3CreateWorld aborts the host.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
New native object ymir_box3d_soa (ABI 1): gravity, free rotation, spheres and static boxes,
one worker, state copied once per step into contiguous lanes that a caller reads in place.
Managed Box3DSoaWorld/Box3DSoaView expose the lanes as spans. The planar retained session is
unchanged. Tests: fall and rest, in-place reads, bit-for-bit repeat runs.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
