refactor(button): improve MD3 compliance and modernize content API

Refactor Button 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**

- Remove implicit text child handling
- Improve icon + label composition
- Standardize loading and disabled states
- Improve ripple and state layer behavior
- Reduce nested render structure
- Improve accessibility semantics

**Proposed API Direction**

Instead of:

`Create`

Prefer:

``

**Performance Opportunities**

- Memoize content container
- Avoid cloning children
- Reduce dynamic style allocations
- Optimize ripple rendering