refactor: remove legacy assistant compatibility

frontend/src/components/workflow/panels/MessageNodePanel.tsx

@@ -14,7 +14,6 @@ import {
 import { Textarea } from "@/components/ui/textarea";
 
 import {
-  messageCompletionPolicy,
   type MessageCompletionPolicy,
   type WorkflowNodeData,
 } from "../specs";
@@ -51,17 +50,13 @@ export function MessageNodePanel({
   set: (key: string, value: unknown) => void;
   setPatch: (patch: Partial<WorkflowNodeData>) => void;
 }) {
-  const completionPolicy = messageCompletionPolicy(draft);
+  const completionPolicy = draft.completionPolicy ?? "playback";
   const completionDescription = COMPLETION_OPTIONS.find(
     (option) => option.value === completionPolicy,
   )?.description;
 
   const selectCompletionPolicy = (value: MessageCompletionPolicy) => {
-    setPatch({
-      completionPolicy: value,
-      requireConfirmation: undefined,
-      showMessage: undefined,
-    });
+    setPatch({ completionPolicy: value });
   };
 
   return (