Ambushed teleports carry their destination; room 59UN unstuck (rev 35)

An ambush springing TELEPORT OPPONENT opened a stack with params null —
the spring bypasses cast validation and nothing ever asked where the
victim goes — and resolution crashed on the missing cell, wedging the
room 'waiting on Automaton'. Three layers:
- Crash guards: teleport-opponent and mental-force fizzle gracefully on
  a destination-less stack (ungated: no stored command had resolved one).
- The trap commits its destination when laid: setAmbush carries a cell
  ('wherever you say', said in advance), the spring passes it into the
  stack, and the client's arming flow asks for the click.
- Rev 35 refuses arming those spells without a destination; older
  ledgers armed blind and their springs fizzle.
All ledgers verified before deploy.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0138A8CjeQRpvzKxuMfz1Bqc

packages/engine/test/game.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from "vitest";
 import { giveCard } from "./helpers";
+import { edgeKey } from "../src/board";
 import {
   applyCommand,
   activePlayer,
@@ -312,3 +313,50 @@ describe("the Ward is played in the moment (rules rev 31)", () => {
     expect(r.ok).toBe(false);
   });
 });
+
+describe("an ambushed teleport carries its destination (rules rev 35)", () => {
+  it("the trap springs and the victim lands where the trapper said", () => {
+    let { state } = createGame({ playerIds: ["trapper", "prey"], seed: 42, sets: ["basic", "expansion1"], deckRev: 35 });
+    for (let guard = 0; guard < 10 && !(state.players[state.turn.activeIndex]!.id === "trapper" && state.turn.round > 1); guard++) {
+      const r = applyCommand(state, state.players[state.turn.activeIndex]!.id, { type: "endTurn", draw: 0 });
+      if (!r.ok) throw new Error(r.error);
+      state = r.state;
+    }
+    const trapper = state.players.find((p) => p.id === "trapper")!;
+    const prey = state.players.find((p) => p.id === "prey")!;
+    giveCard(state, "trapper", "interrupt", "I", 0);
+    giveCard(state, "trapper", "teleport-opponent", "TO", 1);
+    // Arming without a destination is refused; with one it is stored.
+    const bad = applyCommand(state, "trapper", {
+      type: "setAmbush", instanceId: "interrupt#I", trigger: { kind: "near" },
+      spellInstanceId: "teleport-opponent#TO",
+    });
+    expect(bad.ok).toBe(false);
+    const dest = { x: trapper.home.x, y: trapper.home.y === 0 ? 1 : trapper.home.y - 1 };
+    let r = applyCommand(state, "trapper", {
+      type: "setAmbush", instanceId: "interrupt#I", trigger: { kind: "near" },
+      spellInstanceId: "teleport-opponent#TO", cell: dest,
+    });
+    if (!r.ok) throw new Error(r.error);
+    state = r.state;
+    state = applyCommand(state, "trapper", { type: "endTurn", draw: 0 }).ok
+      ? (applyCommand(state, "trapper", { type: "endTurn", draw: 0 }) as { state: typeof state }).state : state;
+    // The prey walks adjacent; the trap springs; the prey passes; they land
+    // at dest. (Re-find both: applyCommand clones made the handles stale.)
+    const trapperNow = state.players.find((p) => p.id === "trapper")!;
+    const preyNow = state.players.find((p) => p.id === "prey")!;
+    const below = trapperNow.position.y >= 2;
+    preyNow.position = { x: trapperNow.position.x, y: trapperNow.position.y + (below ? -2 : 2) };
+    const dir = below ? "S" : "N";
+    state.edgeOverrides[edgeKey(preyNow.position, dir)] = "open";
+    r = applyCommand(state, "prey", { type: "move", direction: dir });
+    if (!r.ok) throw new Error(r.error);
+    state = r.state;
+    expect(state.stack?.attackCard?.cardId).toBe("teleport-opponent");
+    expect(state.stack?.params?.cell).toEqual(dest);
+    r = applyCommand(state, "prey", { type: "pass" });
+    if (!r.ok) throw new Error(r.error);
+    state = r.state;
+    expect(state.players.find((p) => p.id === "prey")!.position).toEqual(dest);
+  });
+});