Allow a pattern of multiple actions per turn. Card options can "refund" an action to the player if they should be free, or zero out the remaining actions if they should force the turn to go directly to the simulation step.
Deck does enough stuff it should be its own thing; its internal representation might change to make multiple insertions not quadratic, among other reasons. Currently it just does the obvious stuff, though. Allows inserting cards in random or specific slots and drawing cards. Shuffling a range of the deck comes later.