refactor(types): unify handler and middleware definitions

- Consolidates `Handler` and `Middleware` types under `Types` module
- Replaces `IHandler` and `IMiddleware` interfaces with typed functions
- Simplifies imports and improves code organization
- Enhances debugging with named handlers and middlewares

src/Types/mod.ts

@@ -1,6 +1,8 @@
 // deno-coverage-ignore-file
 
 export type { DeepPartial } from './DeepPartial.ts';
+export { isHandler } from './Handler.ts';
+export type { Handler } from './Handler.ts';
 export type { HttpErrorHandler } from './HttpErrorHandler.ts';
 export { isHttpMethod, validHttpMethods } from './HttpMethod.ts';
 export type { HttpMethod } from './HttpMethod.ts';
@@ -34,6 +36,8 @@ export {
     validHttpStatusCodes,
 } from './HttpStatusCode.ts';
 export type { HttpStatusCode } from './HttpStatusCode.ts';
+export { isMiddleware } from './Middleware.ts';
+export type { Middleware } from './Middleware.ts';
 export type { Params } from './Params.ts';
 export type { Query } from './Query.ts';
 export type { RegisterRoute } from './RegisterRoute.ts';