The orbit rig read the wheel unfiltered for zoom, so scrolling a paint-mode
scroll list also zoomed the camera. Gate the zoom behind a shared
InputUtil.PointerOverUi() helper (EventSystem raycast); MeshPainter's private
IsPointerOverUi() now delegates to the same helper (DRY).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>