feat(performance): Add async utility functions and filesystem utilities

- Implemented async utilities including delay, retryWithBackoff, withTimeout, parallelLimit, debounceAsync, AsyncMutex, and CircuitBreaker.
- Created tests for async utilities to ensure functionality and reliability.
- Developed AsyncFileSystem class with methods for file and directory operations, including ensureDir, readFile, writeFile, remove, and more.
- Added tests for filesystem utilities to validate file operations and error handling.

ts/core/utils/index.ts

@@ -13,3 +13,5 @@ export * from './shared-security-manager.js';
 export * from './event-system.js';
 export * from './websocket-utils.js';
 export * from './logger.js';
+export * from './async-utils.js';
+export * from './fs-utils.js';