refactor(card): modernize composition model and improve MD3 behavior

[ruben-rebelo]

Refactor Card 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

• Reduce dependence on deeply nested children
• Improve Card.Content / Card.Actions architecture
• Improve elevation and surface behavior
• Improve shape and outlined variants
• Simplify internal spacing rules

Proposed API Direction

Introduce clearer slot-based APIs:
<Card title="Title" subtitle="Subtitle" content={<Text>Content</Text>} actions={[...]} />

Performance Opportunities

• Reduce nested wrappers
• Optimize pressable behavior
• Avoid unnecessary subtree re-renders
• Improve memoization boundaries

[adrcotfas]

Important

See #4949 for more details