Implement GJK (Gilbert-Johnson-Keerthi) overlap detection and EPA
(Expanding Polytope Algorithm) penetration resolution for arbitrary
convex collider pairs. Used as the fallback narrow phase for any
combination involving Capsule, while Sphere/Box specialized routines
are preserved for performance.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Add Capsule { radius, half_height } to the Collider enum, with AABB
computation and ray-vs-capsule intersection support. The capsule is
oriented along the Y axis (cylinder + two hemisphere caps).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Implements resolve_collisions() with impulse-based velocity correction and
Baumgarte-style position correction, plus physics_step() combining integrate,
detect_collisions, and resolve_collisions.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
