Adding acceleration toward a planet is not enough. The gravity direction defines local down, and the tangent plane derived from it defines the character’s usable movement frame.
Camera yaw must rotate around local up. Movement input must be projected onto the tangent. Floor traces run along local down. Animation speed must ignore velocity normal to the local surface rather than blindly discarding world Z.
The decision was to make the gravity-local basis an explicit shared input. Every system deriving its own approximation would eventually disagree at a pole, during a transition or after a floating-origin rebase.