fix: fork session (#7219)

Author: angiejones

ui/desktop/src/components/ProgressiveMessageList.tsx

@@ -36,7 +36,7 @@ interface ProgressiveMessageListProps {
   // Custom render function for messages
   renderMessage?: (message: Message, index: number) => React.ReactNode | null;
   isStreamingMessage?: boolean; // Whether messages are currently being streamed
-  onMessageUpdate?: (messageId: string, newContent: string) => void;
+  onMessageUpdate?: (messageId: string, newContent: string, editType?: 'fork' | 'edit') => void;
   onRenderingComplete?: () => void; // Callback when all messages are rendered
   submitElicitationResponse?: (
     elicitationId: string,

ui/desktop/src/components/UserMessage.tsx

@@ -80,7 +80,7 @@ export default function UserMessage({ message, onMessageUpdate }: UserMessagePro
 
       setIsEditing(false);
 
-      if (editContent.trim() === textContent.trim()) {
+      if (editType === 'edit' && editContent.trim() === textContent.trim()) {
         return;
       }