refactor(list-item): improve layout system and remove implicit child composition

Refactor ListItem 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**

- Replace arbitrary child composition with explicit slots
- Improve left/right accessory APIs
- Standardize spacing and density
- Improve multiline layout behavior
- Improve virtualization friendliness

**Proposed API Direction**

Instead of:

`

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Prefer:

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**Performance Opportunities**

- Improve rendering in FlatList usage
- Memoize accessories
- Reduce layout passes
- Avoid child traversal