feat: implement comprehensive frontend design improvements

[ryanaidilp]

Summary

• Implement complete reusable component architecture (BaseButton, BaseCard, BaseBadge, BaseSkeleton)
• Add dark/light theme system with ThemeToggle component and useTheme composable
• Enhance CodeBlock component with dual theme support and advanced syntax highlighting features
• Add LazyImage component with intersection observer for improved performance
• Implement PageTransition system with multiple animation types (fade, slide, scale)
• Update core styles with comprehensive accessibility improvements and responsive design
• Enhance Navigation component with better theme integration
• Update Home view with improved component architecture
• Configure Tailwind with extended theme colors and utility classes

Test Plan

• Verify all new components render correctly in light/dark themes
• Test responsive design across mobile and desktop breakpoints
• Validate accessibility features (keyboard navigation, screen readers)
• Ensure page transitions work smoothly between routes
• Confirm theme toggle persists user preference
• Test lazy image loading with intersection observer
• Verify syntax highlighting works in CodeBlock component

Technical Details

• All components follow Vue 3 Composition API patterns with TypeScript
• Theme system uses CSS variables for seamless light/dark switching
• Components are fully accessible with ARIA labels and keyboard support
• Performance optimized with lazy loading and intersection observer
• Maintains backward compatibility with existing codebase