Better handling of CoroutineContext in traces

[pyricau]

CoroutineContext is an immutable linked list but also, conceptually, a map.

If we see a chain of coroutine context going through the left field (actually, maybe specifically CombinedContext) then we could flatten that as a single object in the trace, and leverage the array syntax to surface the coroutine key and the coroutine value.

There's also potentially for traversing all of the context and pulling useful information. E.g. if we can pull out job status that'd be super useful.