refactor(radio-button): modernize selection model and improve MD3 compliance

Refactor RadioButton to improve Material Design 3 compliance, remove problematic children patterns, improve performance characteristics, and modernize the public API.

**Problems**

- Current API relies heavily on children composition in ways that are difficult to optimize
- Internal layout logic is tightly coupled to arbitrary child structures
- MD3 behaviors and visuals are not fully aligned with current Material guidelines
- Rendering performance can degrade in large lists or frequently updated screens
- Type safety and discoverability of the API can be improved
- The component has inconsistent behavior between platforms and edge cases

**Focus Areas**

- Improve RadioButton.Group architecture
- Improve accessibility semantics
- Improve spacing and density consistency
- Simplify internal selection propagation

**Proposed API Direction**

``

**Performance Opportunities**

- Reduce context-driven rerenders
- Improve group memoization
- Simplify animation paths

首先追踪现有的 RadioButton 和 RadioButton.Group 实现，以及当前如何处理选择、无障碍、间距和动画。将其行为与提议的 value/onValueChange API 以及当前的 Material Design 3 指南进行比较。完成的标准是：具备文档化的设计和已实现的组架构，并在各个平台上保持语义、密度、选择传播和重新渲染行为的一致性。

由索引模型根据 Issue 内容生成。