[BREAKING] Python: Move single-config fluent methods to constructor parameters (#3693)

* Move single-config fluent methods to constructor parameters

* Updates

* Adjust magentic and group chat

python/samples/getting_started/workflows/state-management/state_with_agents.py

@@ -189,7 +189,7 @@ async def main() -> None:
     #     False -> submit_to_email_assistant -> email_assistant_agent -> finalize_and_send
     #     True  -> handle_spam
     workflow = (
-        WorkflowBuilder()
+        WorkflowBuilder(start_executor="store_email")
         .register_agent(create_spam_detection_agent, name="spam_detection_agent")
         .register_agent(create_email_assistant_agent, name="email_assistant_agent")
         .register_executor(lambda: store_email, name="store_email")
@@ -197,7 +197,6 @@ async def main() -> None:
         .register_executor(lambda: submit_to_email_assistant, name="submit_to_email_assistant")
         .register_executor(lambda: finalize_and_send, name="finalize_and_send")
         .register_executor(lambda: handle_spam, name="handle_spam")
-        .set_start_executor("store_email")
         .add_edge("store_email", "spam_detection_agent")
         .add_edge("spam_detection_agent", "to_detection_result")
         .add_edge("to_detection_result", "submit_to_email_assistant", condition=get_condition(False))

python/samples/getting_started/workflows/state-management/workflow_kwargs.py

@@ -88,7 +88,7 @@ async def main() -> None:
     )
 
     # Build a simple sequential workflow
-    workflow = SequentialBuilder().participants([agent]).build()
+    workflow = SequentialBuilder(participants=[agent]).build()
 
     # Define custom context that will flow to tools via kwargs
     custom_data = {