Idiot enforces its card (rev 23) + attack sight-line tracing

Rules rev 23 — IDIOT, per the card and FAQ:
- No handling items: pick up / drop of treasures and objects refused
  (dropping was the exploit: capturing a stolen treasure on your own home,
  or dropping your own treasure underfoot for an instant cure)
- No punching, no thrown dagger / large rock (attacks on players)
- No effect on a victim already carrying one of their own treasures
Ungated (permissive): counteractions are now castable while idiotized (the
one thing the card expressly allows — the gate wrongly blocked them), and
goal-aiding spells (IDIOT_AIDS: destroy-wall, teleport, mad-dash, ...) per
the FAQ's 'you could, however, destroy a wall'.

Sight tracing: while an LOS attack sits on the stack, the board draws the
line it traveled — straight when direct, leg by leg through both warp
mouths (with pulsing rings) when the maze's wraparound carried it. Engine
traceSight/traceSightFor/stackSightTrace; overlay in Board.svelte; shown
live and in replays. Verified against H3PC's cross-board Idiot cast.

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

packages/engine/test/expansion-combat.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { applyCommand, activePlayer, boardView, gameLos, sustainedOn } from "../src/game";
+import { applyCommand, activePlayer, boardView, createGame, gameLos, sustainedOn } from "../src/game";
 import { cellKey, stepTarget } from "../src/board";
 import type { CardInstance } from "../src/cards";
 import { newExpansionGame as newGame, must, giveCard, toRound2, faceOff, castAt } from "./helpers";
@@ -161,6 +161,58 @@ describe("expansion combat cards", () => {
       expect(r.error).toMatch(/blocked/);
     }
   });
+
+  it("idiot at rev 23 forbids item handling and punches but allows counteractions", () => {
+    let { state } = createGame({
+      playerIds: ["alice", "bob"], seed: 42, sets: ["basic", "expansion1"], deckRev: 23,
+    });
+    state = toRound2(state);
+    const { attacker, defender } = faceOff(state);
+    // The victim carries an OPPONENT'S treasure into the spell.
+    const d = state.players.find((p) => p.id === defender)!;
+    const stolen = state.treasures.find((t) => t.owner === attacker)!;
+    stolen.carriedBy = defender;
+    stolen.position = null;
+    d.carriedTreasureId = stolen.id;
+    const id = giveCard(state, attacker, "idiot");
+    state = castAt(state, attacker, defender, id);
+    expect(sustainedOn(state, defender, "idiot").length).toBe(1);
+    state = must(state, attacker, { type: "endTurn", draw: 0 });
+
+    // No dropping the carried treasure (no capturing it on your home, either).
+    const drop = applyCommand(state, defender, { type: "dropTreasure" });
+    expect(drop.ok).toBe(false);
+    if (!drop.ok) expect(drop.error).toMatch(/treasure/);
+    // No punching the tormentor.
+    expect(applyCommand(state, defender, { type: "punch", targetId: attacker }).ok).toBe(false);
+    // Goal-aiding spells stay castable (FAQ: "You could, however, destroy a wall").
+    const sp = giveCard(state, defender, "speed", "SP", 0);
+    expect(applyCommand(state, defender, { type: "cast", instanceId: sp.instanceId }).ok).toBe(true);
+    // Counteractions are expressly allowed: absorb an incoming fireball.
+    state = must(state, defender, { type: "endTurn", draw: 0 });
+    const fb = giveCard(state, attacker, "fireball", "F", 0);
+    state = must(state, attacker, {
+      type: "cast", instanceId: fb.instanceId, target: { kind: "player", playerId: defender },
+    });
+    giveCard(state, defender, "absorb-spell", "AB", 1);
+    expect(applyCommand(state, defender, { type: "counteract", instanceId: "absorb-spell#AB" }).ok).toBe(true);
+  });
+
+  it("idiot at rev 23 has no effect on a victim carrying their own treasure", () => {
+    let { state } = createGame({
+      playerIds: ["alice", "bob"], seed: 42, sets: ["basic", "expansion1"], deckRev: 23,
+    });
+    state = toRound2(state);
+    const { attacker, defender } = faceOff(state);
+    const d = state.players.find((p) => p.id === defender)!;
+    const own = state.treasures.find((t) => t.owner === defender)!;
+    own.carriedBy = defender;
+    own.position = null;
+    d.carriedTreasureId = own.id;
+    const id = giveCard(state, attacker, "idiot");
+    state = castAt(state, attacker, defender, id);
+    expect(sustainedOn(state, defender, "idiot").length).toBe(0);
+  });
 });
 
 describe("swap home bases", () => {