Two-player decks shed LIFESAVER, as the card itself instructs

"Not applicable in a 2-player game." — the card face. New games deal
from deck revision 2, which removes it when exactly two wizards sit
down; three or more keep it. The revision travels in GameConfig and
the persisted start line, and stored games without one replay against
the original build — changing an existing game's deck composition
would scramble its deterministic replay. Test pins all three cases:
removed at two, present at three, present in legacy two-player games.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/engine/test/casting.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { applyCommand, activePlayer, boardView } from "../src/game";
+import { applyCommand, activePlayer, boardView, createGame } from "../src/game";
 import { cellKey, edgeKey, hasLineOfSight, neighbor, type Side } from "../src/board";
 import type { CardInstance } from "../src/cards";
 import { newGame, must, giveCard, toRound2, faceOff } from "./helpers";
@@ -314,3 +314,17 @@ describe("stored-log compatibility", () => {
     expect(state.players.find((p) => p.id === defender)!.life).toBe(15 - 5); // fireball: 2 + the 3
   });
 });
+
+describe("deck revisions", () => {
+  it("revision 2 removes LIFESAVER at two players, and only there", () => {
+    const two = createGame({ playerIds: ["a", "b"], seed: 9, sets: ["basic", "expansion1"], deckRev: 2 });
+    const inGame = (s: typeof two.state) =>
+      [...s.deck, ...s.discard, ...s.players.flatMap((p) => p.hand)].some((c) => c.cardId === "lifesaver");
+    expect(inGame(two.state)).toBe(false);
+    // Three players keep it; old two-player games (no deckRev) keep it too.
+    const three = createGame({ playerIds: ["a", "b", "c"], seed: 9, sets: ["basic", "expansion1"], deckRev: 2 });
+    expect(inGame(three.state)).toBe(true);
+    const legacy = createGame({ playerIds: ["a", "b"], seed: 9, sets: ["basic", "expansion1"] });
+    expect(inGame(legacy.state)).toBe(true);
+  });
+});