I know that stories on a Next-Gen kanban board drop off of the right-most column after 2 weeks, but what happens to them? Would we be able to find and re-open them later after they've dropped off the board? We're trying to set up a flow where we can "release" stories by putting them into that last column, but then be able to look at them later to double-check that they were implemented as designed or compare designs to more recent work.