Duels record the rules revision they began under

CURRENT_RULES is stamped on the start line and the game state, and a
ledger replays under the revision it recorded (1 when it has none), so a
future fix that changes how a past turn resolves can keep the old path
for old duels. The reports desk skill now says when to bump it: only
when the deploy gate flags ledgers.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0141G6xqLeNRYEtviLWSB5Up

src/lib/game/duel.svelte.ts

@@ -179,6 +179,7 @@ function loadSaved(): SavedDuel | null {
 		// Saves at this version may lack fields that came later; the engine expects them present.
 		saved.state.seats ??= Object.keys(saved.state.wizards);
 		saved.state.lessonsShown ??= [];
+		saved.state.rules ??= 1;
 		if (saved.state.lastTurn) {
 			saved.state.lastTurn.events ??= [];
 			saved.state.lastTurn.lessons ??= [];

src/lib/game/state.ts

@@ -129,7 +129,21 @@ export interface Outcome {
 	reason: string;
 }
 
+/**
+ * The rules revision a duel resolves under. A duel keeps the revision it began
+ * with, so a ledger replays to what its players saw even after the resolver
+ * changes. Bump this only when a fix changes how an already-played turn would
+ * resolve, which the deploy gate (deploy/verify-ledgers.sh) shows by flagging
+ * ledgers; a fix that diverges from no ledger ships without a bump. Keep the
+ * old path behind `state.rules < N` and pin both with tests.
+ *
+ *   1  Bartle's text as first implemented (2026-09-22).
+ */
+export const CURRENT_RULES = 1;
+
 export interface GameState {
+	/** The revision this duel resolves under; see CURRENT_RULES. */
+	rules: number;
 	turn: number;
 	/** Seats in table order; every wizard in play, whether still standing or not. */
 	seats: WizardId[];
@@ -235,9 +249,10 @@ function makeWizard(id: WizardId, name: string): WizardState {
 	};
 }
 
-export function createGame(names: Record<WizardId, string>, seed = Date.now()): GameState {
+export function createGame(names: Record<WizardId, string>, seed = Date.now(), rules = CURRENT_RULES): GameState {
 	const seats = Object.keys(names);
 	return {
+		rules,
 		turn: 0,
 		seats,
 		wizards: Object.fromEntries(seats.map((id) => [id, makeWizard(id, names[id])])),

src/lib/game/view.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { SPECTATOR, createGame } from './state';
+import { CURRENT_RULES, SPECTATOR, createGame } from './state';
 import { viewFor } from './view';
 
 /** Three wizards; B's first gestures were hidden from C alone. */
@@ -30,3 +30,10 @@ describe('the view a room sends', () => {
 		expect(view.log.map((l) => l.text)).toEqual(['Nothing else happened.']);
 	});
 });
+
+describe('the rules revision', () => {
+	it('is stamped on a new duel and kept from a ledger that recorded one', () => {
+		expect(createGame({ A: 'Aldric', B: 'Bryn' }).rules).toBe(CURRENT_RULES);
+		expect(createGame({ A: 'Aldric', B: 'Bryn' }, 1, 1).rules).toBe(1);
+	});
+});