Add history for "Reason for change" for class creation

We integrated the history for most "commit" actions (as described in #261) , but we did not do it for the Class Creation action, as it can be seen in this screenshot of the "Create Class" dialog:

<img width="875" height="748" alt="Image" src="https://github.com/user-attachments/assets/701aeeb7-c628-47bb-8f29-a2b61df41d0b" />


The reason for change should be integrated also here!