Camera orbit turntable with spring arm for product viewer

Setup: SceneComponent(root) → SpringArmComponent(child) → CameraComponent(child). SpringArm: UsePawnControlRotation=false, TargetArmLength=500. Orbit: InputAxis MouseX → MakeRotator(0,0,Value*Sensitivity) → AddRelativeRotation(SpringArm). Zoom: MouseWheel → GetTargetArmLength → Subtract(Current, Axis*Step) → FClamp(Min,Max) → SetTargetArmLength.