Workflow Editor crashes when manual editing is happening while AI edit is in progress

Describe the bug

This happens when you change a node while the AI assistant isn't done with its edits of the workflow.

1. ask the AI to change a node
2. as soon as the change is visible on the screen but the AI response is still streaming. change the node to something else
3. the workflow editor breaks.
   (assumption: probably because you changed the data the AI assistant is working with)

Version number The version of Lightning you have seen the bug on.

If you're running on a tagged version, include the number: vX.Y.Z

If you're running locally with an unreleased version, the commit sha: 84b1bdc

I have reproduced this locally on main:

• Yes
• No

To Reproduce Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior A clear and concise description of what you expected to
happen.

Screenshots If applicable, add screenshots to help explain your problem.

Additional context Add any other context about the problem here.

Start in the Workflow Editor by reproducing the sequence described: begin an AI node edit, change the node while the response is streaming, and observe the failure. Trace the error from that interaction and verify that manual edits no longer break the editor while the AI response continues.