Add TypeScript files with the patterns

Summary by Bito

This PR introduces multiple TypeScript files establishing structured coding patterns across the application. It adds a new React component with state management and async operations, along with declaration modules showcasing TypeScript features. The changes improve code clarity, maintainability, and type safety while reinforcing a modular approach with strongly-typed patterns.

Unit tests added: False

Estimated effort to review (1-5, lower is better): 2