- Add PlayerCharacterController script: CharacterController-based
movement (camera-relative WASD), jump, gravity, rotate-toward-movement
and slope sliding so the player slides off surfaces/edges steeper than
the slope limit instead of balancing on them.
- Update SampleScene: add Player (with CharacterController), ground plane
and obstacle cubes; parent the paintable paintman_UV under the Player.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
