v0.5.0 — multiplayer Phases 2 and 3: a server that runs a game and survives being restarted

Phases 0-1 shipped in v0.4.0 (seat/identity split, per-player turn state, the Session boundary).
This lands Phase 2 (server core, one game, no lobby) and Phase 3 (persistence and resumption) per
docs/architecture/multiplayer.md §12. Phases 4-6 (lobby/reconnection, the 22 opponent-directed
cards, StartOS packaging) are still ahead.

Phase 2: src/server/session.ts hosts a game in pure logic (no sockets) on top of game.ts's existing
Game/submit/currentActor/actionMenu; it verifies seat === currentActor(game) itself before calling
submit, since submit() trusts its caller and a server can't. src/server/http.ts and index.ts add
POST /api/game, GET /api/stream (SSE, per-seat), POST /api/intent, and static serving of dist/.
src/sim/frame-delta.ts is a purpose-built per-seat board delta for one live push at a time. Found
and fixed along the way: actionMenu(game, seat) only used seat for the hand field, so a server
computing every connected seat's Menu would have handed the acting player's legal moves to a
waiting seat. Verified with a live end-to-end smoke test (2-player game, two SSE streams, a
rejected intent from the wrong seat, an idempotent resend) plus test/server/session.test.ts and
test/redaction.test.ts. Not verified: an actual browser (none available in this environment).

Phase 3: src/server/persistence.ts writes game.json and turn-timings.json, atomic-rewrite-then-
rename. game.ts gained fromMultiplayerSave, fixing a narration-attribution bug found while testing
it (fromSave's replay loop drops the actor argument, invisible in solitaire, unreadable the moment
there's more than one seat — fromSave itself still has this gap, deliberately untouched). Verified
live: server killed and restarted mid-game, both seats reconnected exactly where they left off.

Two rules bugs found while building this: the New Train phase never implemented its car-placement
round (every car of every train was placed by the Superintendent alone, in every mode, all along —
now reads the round position off tray.consist.length); and victory conditions are now one shared,
configurable GameConfig set across solitaire/competitive/coop instead of a fixed length lookup and
a dead firstToTarget condition.

Also folds in the three fixes already released on the patch line as v0.4.9b/c/d: a switching
train's crew badge failing to draw once it left the Office square, an unload that always took the
westmost car regardless of which was picked, and a legal decision that could render with zero
buttons.

docs/testing/0.5.0-test-plan.md and three reported-bug save files (docs/station-master-seed*.json)
included for reproducibility. tools/jitsi-harness/ deliberately left untracked — unrelated
side-project work, not part of this release. 635 tests, 0 failures.

src/sim/compare.ts

@@ -31,6 +31,12 @@
 
 import { pump } from '../engine/advance.ts';
 import { createGame } from '../engine/setup.ts';
+import {
+  DEFAULT_MAX_COLLISIONS_PER_DAY,
+  DEFAULT_MAX_COLLISIONS_TOTAL,
+  collectiveRevenueFloor,
+  lengthProfile,
+} from '../engine/content.ts';
 import type { GameLength } from '../engine/content.ts';
 import type { GameConfig, GameMode } from '../engine/state.ts';
 import type { BotPolicy, BotTweaks } from './bot.ts';
@@ -56,17 +62,24 @@ export type PairedResult = {
   variantStats: GameStats[];
 };
 
-const SOLO = (length: GameLength, mode: GameMode): GameConfig => ({
-  mode,
-  victory: 'highestAfterDays',
-  length,
-  optionalRules: {
-    reducedVisibility: false,
-    sisterTrains: false,
-    employeeRotation: false,
-    emergencyToolbox: false,
-  },
-});
+// Always one bot (`runOne` below), so the revenue floor is `collectiveRevenueFloor(1, days)`.
+const SOLO = (length: GameLength, mode: GameMode): GameConfig => {
+  const days = lengthProfile(length).days;
+  return {
+    mode,
+    days,
+    minCombinedRevenue: collectiveRevenueFloor(1, days),
+    maxCollisionsPerDay: DEFAULT_MAX_COLLISIONS_PER_DAY,
+    maxCollisionsTotal: DEFAULT_MAX_COLLISIONS_TOTAL,
+    pvpCardsAllowed: false,
+    optionalRules: {
+      reducedVisibility: false,
+      sisterTrains: false,
+      employeeRotation: false,
+      emergencyToolbox: false,
+    },
+  };
+};
 
 /**
  * One game, one seed, one policy.