refactor(bottom-navigation): align with MD3 navigation behavior

[ruben-rebelo]

Refactor BottomNavigation 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 active indicator implementation
• Improve shifting behavior
• Improve lazy screen rendering integration
• Improve badge handling

Performance Opportunities

• Reduce navigation item rerenders
• Improve animated transitions
• Optimize route updates