fix(streams): tighten stream typings and guard optional runtime paths for duplex and wrapper utilities

ts/smartstream.functions.ts

@@ -1,4 +1,4 @@
-import { type TransformOptions } from 'stream';
+import { type DuplexOptions } from 'stream';
 import { SmartDuplex } from './smartstream.classes.smartduplex.js';
 
 export interface AsyncTransformFunction<TInput, TOutput> {
@@ -7,7 +7,7 @@ export interface AsyncTransformFunction<TInput, TOutput> {
 
 export function createTransformFunction<TInput, TOutput>(
   asyncFunction: AsyncTransformFunction<TInput, TOutput>,
-  options?: TransformOptions
+  options?: DuplexOptions
 ): SmartDuplex {
   const smartDuplexStream = new SmartDuplex({
     ...options,