v0.6.0 — saves survive a release, Employee Rotation is real, and the lobby

asks what game you want

Three queued items. The last matters most.

A RELEASE NO LONGER DESTROYS EVERY GAME IN PROGRESS.

Four consecutive releases killed every game on the box, one of them a
release that changed only how the board is drawn. The reasoning behind the
refusal was always right — a move legal under old rules may not be legal
under new ones, and half-replaying a save is worse than refusing it. The
TEST was wrong: it compared engineVersion for exact equality, and that
stamp is the package version, which moves for a CSS fix.

Whether a save still replays has an exact answer, so it is now asked
directly. loadGame reads the file and judges nothing; tryResumeSession
replays the intents and reports the first one the engine refuses. A save
stamped with a version this server has never run resumes fine provided its
moves replay — verified against a file hand-stamped 0.4.9-ancient. One that
genuinely does not replay is still refused, but the log names the move
rather than two version strings: "move 3 of 8 (localOps.choose) is rejected
by the current rules with OPTION_ALREADY_CHOSEN".

fromMultiplayerSave had to stop lying first. It has always stopped at the
first unacceptable intent and done so in silence, which was survivable only
because the version gate meant a doomed replay was never attempted. Now
that the replay IS the check, it returns where it stopped and why.

Deliberately not done: resuming a partly-replayable game at its last good
move. That silently rewinds a game to a position nobody played to while
every browser holding a later Frame carries on unaware. Refusing leaves the
file intact, so putting the previous version back still recovers it.

EMPLOYEE ROTATION IS IMPLEMENTED, SISTER TRAINS IS DELETED.

Two of the four optional-rule flags were read by nothing at all. Employee
Rotation is four lines in advance.ts, because the seat/player split (D9)
exists for precisely this rule: seating is the only thing that moves, so
Revenue, hands, the Superintendent and whose turn it is travel with the
player, and the Office, district, grid and any trains standing in it stay
with the chair. Inheriting the district you move into is the point of the
rule, not a side effect. "Left" is seat + 1, matching playerLeftOf.

Sister Trains is deleted rather than built: Q9 records that the Second
Section card supersedes it, and that card exists, so the flag was a toggle
for a rule the game no longer has.

THE LOBBY ASKS WHAT GAME YOU WANT TO PLAY.

Creating a game asked for a name, a mode and a table size; every other dial
was hardcoded. A Game settings block now carries the same set the solitaire
dialog does — seed, starting hand, the three revenue rates, Days, the
combined-Revenue floor, both collision caps, the opponent-card toggle —
plus the three surviving optional rules. Mode and table size set the
defaults and everything stays editable. The seed is honoured, so a game can
be reproduced or compared.

Verified: 682 tests pass (679 + 3). The rotation tests were mutation-checked
both ways — disabling the rotation and turning the table the wrong way each
fail the suite. Live: a save stamped 0.4.9-ancient resumed, an injected
illegal move was refused by name, and a create with every dial set to a
non-default value came back out of game.json with all of them intact,
including seed 777.

Two of my own assertions were wrong on the way and the tests caught them:
the Fedora legitimately passes at Stage 12 (§5) so it cannot be compared
against its own earlier value, and dispatchUsedToday is cleared at every
Day boundary so it cannot mark a district.

test/multiplayer.test.ts

@@ -12,14 +12,14 @@ import assert from 'node:assert/strict';
 
 import { advance, pump } from '../src/engine/advance.ts';
 import { applyIntent, areaAtSeat, areaOf } from '../src/engine/apply.ts';
-import { STAGES_PER_SHIFT, crewTrayCount } from '../src/engine/content.ts';
+import { STAGES_PER_DAY, STAGES_PER_SHIFT, crewTrayCount } from '../src/engine/content.ts';
 import { createGame } from '../src/engine/setup.ts';
 import type { GameConfig, GameState, PlayerIndex } from '../src/engine/state.ts';
 import { coordKey, playerAtSeat, playerLeftOf, seatOf, subdivisions } from '../src/engine/state.ts';
 import { developerBot, playGame } from '../src/sim/bot.ts';
 import { snapshot } from '../src/sim/view.ts';
 import { divisionSvg } from '../src/sim/board-svg.ts';
-import { impediments } from '../src/sim/narrate.ts';
+import { impediments, narrate } from '../src/sim/narrate.ts';
 import { readFileSync, readdirSync } from 'node:fs';
 import { join } from 'node:path';
 import { actionMenu } from '../src/web/game.ts';
@@ -37,7 +37,7 @@ const competitive: GameConfig = {
   maxCollisionsPerDay: 0,
   maxCollisionsTotal: 0,
   pvpCardsAllowed: false,
-  optionalRules: { reducedVisibility: false, sisterTrains: false, employeeRotation: false, emergencyToolbox: false },
+  optionalRules: { reducedVisibility: false, employeeRotation: false, emergencyToolbox: false },
 };
 
 const game = (players: number, seed = 4242): GameState =>
@@ -794,3 +794,81 @@ describe('the map says whose railroad is whose', () => {
     assert.equal(divisionSvg(f.division).includes('bs-owner'), false);
   });
 });
+
+describe('Employee Rotation (Appendix B)', () => {
+  /**
+   * Straight to the Day boundary, which is the only moment a rotation happens — the same shortcut
+   * `advance.test.ts` uses to roll the clock over without playing twelve Stages of real turns.
+   */
+  const atDayEnd = (on: boolean): GameState => {
+    const s = createGame({
+      id: 'rot',
+      seed: 4242,
+      config: { ...competitive, optionalRules: { ...competitive.optionalRules, employeeRotation: on } },
+      playerNames: ['Alice', 'Bob', 'Carol'],
+    });
+    s.clock.stage = STAGES_PER_DAY;
+    s.clock.phase = 'shiftChange';
+    return s;
+  };
+
+  it('is off unless asked for — the clock alone must not move anybody', () => {
+    const s = atDayEnd(false);
+    const before = [...s.seating];
+    advance(s);
+    assert.equal(s.clock.day, 2, 'the clock did not roll over');
+    assert.deepEqual(s.seating, before, 'seats moved with the rule switched off');
+  });
+
+  it('moves every player one chair left at the Day boundary', () => {
+    const s = atDayEnd(true);
+    const before = [...s.seating];
+    advance(s);
+    assert.equal(s.clock.day, 2);
+    // "One chair to the left" is seat + 1, the direction `playerLeftOf` already turns the table.
+    const expected = before.map((_, seat, all) => all[(seat - 1 + all.length) % all.length]!);
+    assert.deepEqual(s.seating, expected);
+    // Everyone moved, and nobody was lost or duplicated on the way round.
+    assert.deepEqual([...s.seating].sort(), [...before].sort());
+    assert.notDeepEqual(s.seating, before);
+  });
+
+  it('takes your points and the Fedora with you, and leaves the district behind', () => {
+    const s = atDayEnd(true);
+    const traveller = 1 as PlayerIndex;
+    s.players[traveller]!.revenue = 17;
+    const seatBefore = seatOf(s, traveller);
+    /**
+     * The Fedora is compared against the SAME game with the rule off, not against its own value
+     * before the advance — Stage 12 is a shift change (§5), so it passes here anyway for reasons
+     * that have nothing to do with rotation. What matters is that moving the chairs does not move
+     * it: it names a player, and players are exactly what the rotation does not renumber.
+     */
+    const control = atDayEnd(false);
+    advance(control);
+    // Identity, not a field: anything mutable is liable to be reset at a Day boundary anyway (the
+    // once-a-Day dispatch reset clears `dispatchUsedToday` right there), and the claim under test
+    // is about which OBJECT is attached to which chair.
+    const districtLeftBehind = areaAtSeat(s, seatBefore);
+
+    advance(s);
+
+    assert.notEqual(seatOf(s, traveller), seatBefore, 'the traveller did not move');
+    assert.equal(s.players[traveller]!.revenue, 17, 'Revenue is keyed by player and must travel');
+    assert.equal(s.clock.superintendent, control.clock.superintendent, 'rotating the chairs moved the Fedora');
+    // The Office stayed exactly where it was, so whoever sits there now inherits it as they find
+    // it. That is the rule rather than a side effect of it — you take over the next station up the
+    // line, mess and all.
+    assert.equal(areaAtSeat(s, seatBefore), districtLeftBehind, 'the district moved with the player');
+    assert.notEqual(areaOf(s, traveller), districtLeftBehind, 'the traveller kept their old district');
+  });
+
+  it('says who is now sitting where, by name', () => {
+    const s = atDayEnd(true);
+    const { events } = advance(s);
+    const rotated = events.find((e) => e.type === 'seatsRotated');
+    assert.ok(rotated, 'no seatsRotated event was emitted');
+    const line = narrate(rotated, { playerName: (p) => s.players[p]!.name }).text;
+    for (const name of ['Alice', 'Bob', 'Carol']) assert.match(line, new RegExp(name));
+  });
+});