FR (Primitives): RatingField primitive

### On which framework/platform would you like to see this feature implemented?

React

### Which UI component is this feature-request for?

Primitive components

### Please describe your feature-request in detail.

Create a RatingField primitive that can be used to select a rating; users can click on a star to select a rating as a form field.

### Please describe a solution you'd like.

This is similar to an exclusive ToggleButtonGroup but with additional styles to show filled states for rating options that are less than what the user selects; for example if the user selects the third star, then the previous two stars would also show as filled.

The current [Rating component](https://ui.docs.amplify.aws/react/components/rating) is not interactive and is only a visual display of a rating.

### We love contributors! Is this something you'd be interested in working on?

- [ ] 👋 I may be able to implement this feature request.
- [ ] ⚠️ This feature might incur a breaking change.

Review the existing Rating component and the exclusive ToggleButtonGroup pattern mentioned in the issue. Define the interactive form-field behavior, including selection and filled states for lower ratings, then verify the design and accessibility requirements before implementation. Done means a React primitive supports selecting a rating with the requested visual behavior.

Written by the indexing model from the issue text.