feat: restructure UI showcase with new sections and components

- Refactored `UIShowcaseClient` to utilize new section components: `ButtonsSection`, `BadgesSection`, `CardsSection`, `FormsSection`, `NavigationSection`, `FeedbackSection`, and `DataDisplaySection`.
- Removed redundant state management and imports, simplifying the component structure.
- Enhanced organization of UI components for improved usability and navigation within the showcase.

src/components/ui-showcase/sections/index.ts

@@ -0,0 +1,7 @@
+export { ButtonsSection } from './ButtonsSection';
+export { BadgesSection } from './BadgesSection';
+export { CardsSection } from './CardsSection';
+export { FormsSection } from './FormsSection';
+export { NavigationSection } from './NavigationSection';
+export { FeedbackSection } from './FeedbackSection';
+export { DataDisplaySection } from './DataDisplaySection';