BREAKING CHANGE(core): major architectural refactoring with fetch-like API

ts/modern/index.ts

@@ -1,6 +1,9 @@
 // Export the main client
 export { SmartRequestClient } from './smartrequestclient.js';
 
+// Export response type from core
+export { SmartResponse } from '../core/index.js';
+
 // Export types
 export type { HttpMethod, ResponseType, FormField, RetryConfig, TimeoutConfig } from './types/common.js';
 export { 
@@ -34,12 +37,12 @@ export function createFormClient<T = any>() {
  * Create a client pre-configured for binary data
  */
 export function createBinaryClient<T = any>() {
-  return SmartRequestClient.create<T>().responseType('binary');
+  return SmartRequestClient.create<T>().accept('binary');
 }
 
 /**
  * Create a client pre-configured for streaming
  */
 export function createStreamClient() {
-  return SmartRequestClient.create().responseType('stream');
+  return SmartRequestClient.create().accept('stream');
 }