Contract 9.12.6

cards_catalog lists the cards the current /cards catalog lists, 123 today, as 9.12.5 did for tower troops (#44). It had also listed eleven cards known only from battles, such as the event-only Super Archers and Party Rocket, with no rarity or cost; /cards never lists them. They stay on the record, and cards_card still answers them by id. A card first seen in a battle on its release day is listed once /cards lists it, which the recorder fetches as soon as it sees one. Behaviour correction; no output-schema change.