- ValidatingMiddleware: Validates inputs against JSON Schema before execution
- Updated README with comprehensive documentation:
  - Middleware pipeline usage
  - CompositeToolProvider for combining providers
  - CachingToolProvider for PSR-16 caching
  - Events for lifecycle tracking
  - Custom middleware examples
  - Production pipeline configuration

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>