Is there a way to massage the state in history mode?

I am developing a game and I allow one of my cards to be "live" (`:live? true` in my data) which means that the clock ticks every few mileseconds. This causes a problem in history mode, because navigating to the previous state would turn `:live?` on what mutates the state right after I navigate one step on the past. I would like to set this flag to `false` either when I am in history mode or when it is saving the snapshots.

Start by tracing the history-mode navigation and the code that saves state snapshots; the issue does not name files or tests. Determine where the :live? flag should be set false, then verify that navigating to a prior state no longer causes the clock to mutate it.

Written by the indexing model from the issue text.