Allow selected cards in authored AI decks

[vanja-ivancevic]

• Prepare authored AI decks for a Fallen Empires dungeon by changing nine cards from AI:RemoveDeck:All to AI:RemoveDeck:Random. Authored deck designers may now use them, while generated decks continue to exclude them.
• Arctic Merfolk: the AI selected the kicked spell when it could reuse Merfolk Traders, but declined to bounce a high-value Colossal Dreadmaw.
• Bamboozle: the AI cast it with sufficient mana and correctly targeted the opponent.
• Diminishing Returns: the AI cast it with a healthy library and refused it with only nine cards remaining, avoiding the ten-card exile near deck-out.
• Floodwater Dam: during the opponent's upkeep, the AI paid a useful X value and selected only opposing lands.
• Mystic Veil: the AI cast it on a creature it controlled.
• Overtaker: the AI stole a tapped opposing Colossal Dreadmaw when it had spare cards, but preserved its valuable last card against a trivial target.
• Phantasmal Terrain: the AI cast it on an opposing non-Island land.
• Thwart: the AI countered a major threat with normal mana, but declined to return three Islands to counter a minor creature.
• Triassic Egg: with two hatchling counters and Deep Spawn in hand, the AI was willing to sacrifice the Egg and use its hatch ability.
• Completed verification covered thirteen controlled gameplay scenarios plus nine card-hint checks. The temporary test files are not included in this PR.