Program value not shown in Source languages

Programs in languages such as JavaScript and Scheme produce values which should be displayed in the REPL. This is currently not working; only explicit `display(...)` calls lead to a display of values in the Source languages.

Example: 

<img width="505" height="467" alt="Image" src="https://github.com/user-attachments/assets/5aea8b5a-9178-4611-a92f-1a9e5e320155" />