can jump when not on gound

[Enhex]

seems to be a problem with Bullet's btKinematicCharacterController::onGround()
that wrongly assumes that if velocity is 0 the character is on the ground, but it's also 0 when reaching trajectory apex.
proper solution is to switch to Jolt Physics.
quick fix is to use collision contact and its normal.

2025-12-23.22-50-20.mp4