Stopwatch-style Work Timer enhancement

Hi! 

I'm Sergey from the Youtrack team. Thank you for your post. 

it requests a user comment

As you mentioned yourself, you can use workflow.message() to show a message to a user. You can also use workflow.check() to prevent users from clicking stop unless they've added a comment. 

saves it in the work item

You can add it to the work item description.

I understand that the code is executed inside GraalVM and the browser dialog window.prompt() is not available.
I believe it would be great to get something like workflow.prompt(), similar to workflow.message().

I'm afraid, as you noticed yourself, that's not feasible from a technical point currently.