Add borderRadius support to RectShape via SpotlightTourProvider

Currently, the RectShape component in package/src/lib/components/tour-overlay/shapes/RectShape.component.tsx renders with a fixed border radius of 4px via the rx and ry props on the AnimatedRect. There is no way to customize the border radius from the SpotlightTourProvider, as it does not expose a borderRadius property.

Expected behavior:

• Ability to set a custom border radius for the rectangular spotlight shape via a prop in SpotlightTourProvider.
• The shape should wrap the target component and match the desired border radius instead of always defaulting to 4px.

Current behavior:

• RectShape always renders with a border radius of 4px, which may not match the target component's border radius.
• No configuration option is available to adjust this value.

Suggested solution:

• Add a borderRadius property to the SpotlightTourProvider and/or allow it to be passed to the RectShape component.
• Propagate the value so that rx and ry on the AnimatedRect reflect the provided value.

Start in package/src/lib/components/tour-overlay/shapes/RectShape.component.tsx and trace how RectShape is configured from SpotlightTourProvider. Check the open pull request linked to this issue before starting. Done means the provider accepts a custom border radius, the value reaches the rectangular spotlight, and the target shape reflects it instead of always using 4px.