Instance versions can be referred to by their key, but for display, a title would be more adequate.

For example in the diagram below (a possible rendering of an ExampleScenario),

"POST task..." is step.title 

"Task" is instance.title

"(Task version 1)" is instance.version.description. This may be too long to display in a compact form.

We should add `title` to instance.version to allow using that for short human-readable representation (in a diagram or a summary table)