Function useRotateTool

Rotate-only Tool. Owns the rotation-handle affordance render layer; the gesture itself flows through rotateAction (declarative binding in useSelectTool.bindings keyed on the rotate-handle affordance hit kind) → dispatcher → preview surface → scene commit.

The legacy useRotate hook is removed — the affordance no longer wraps each region's drag channel; the unwrapped affordance is used purely for the paint + hit-test surface. The dispatcher's affordanceAt pipeline produces rotate-handle hits independently (see src/canvas/affordanceAt.ts), which the useSelectTool rotate binding then routes to rotateAction.