Function axis_step_order 

fn axis_step_order(movement: DVec3) -> [Axis; 3]

Returns the axis step order for collision resolution.

Vanilla’s Direction.axisStepOrder(Vec3) returns:

• YZX if |x| < |z| (move along Z before X)
• YXZ otherwise (move along X before Z)

Y is always first because gravity/vertical movement should be resolved first.