This fixes a bug where if you ran /diff while at turn was running, transcript lines would be added to the end of the diff view. Also, refactor to make this kind of issue less likely in future.
this was causing continuous rerendering when a transcript overlay was present
Fixing merge conflict of this: #2588 https://github.com/user-attachments/assets/392c7c37-cf8f-4ed6-952e-8215e8c57bc4