Thank you for your interest in our product. Having new field such as DoneDate is interesting idea and I've added it to our product backlog. Regarding to Release Report we have such item in the backlog and it might be implemented in future version of TeamPulse. Using the Audit table in our database, we could figure out the "done date" of a story, there just isn't a place in the app yet where we display this information.
the Telerik team