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

[ruben-rebelo]

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:

<List.Item> <CustomContent /> </List.Item>

Prefer:

<List.Item title="Title" description="Description" left={...} right={...} />

Performance Opportunities

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

[adrcotfas]

Important

See #4949 for more details

[adam-sajko]

Looking at this from the #4976 side.

The child composition is in List.Accordion, not in List.Item. List.Item props are $RemoveChildren<typeof TouchableRipple> and the only React.Children in the folder is the accordion one, which #5018 covers. title / description / left / right from Proposed API Direction are on main already too.

The other points are real though. left and right are render props so the caller can't memoize them, that is #5042. There is no React.memo on List.Item either. And on the platform side, alignToTop runs off onTextLayout, which react-native-web doesn't implement, so multiline alignment only works on native. Spacing and multiline layout are in #5041.

So is the composition part meant for the Accordion? Otherwise I would narrow this down to the memo and the web gap.