v0.5.3 — a table you size yourself, and games an administrator can see and end

Both halves came out of playing the StartOS build. The wrapper's health
check and admin actions consume this; they land separately.

The host picks the table size (2-4) when creating a game, and the seats
array is built at that length once. Before, it GREW as people joined, so
the four rows on screen were partly fiction — a 2-player game just started
with a 2-long array, while a host who dropped a bot into a later chair
padded it with a null and silently disabled Start behind a one-line note.
A gap can no longer be written down rather than merely being refused.

That also avoided a trap. Compacting seats at Lobby.Start — the obvious
way to support a "closed" chair — would have shifted the player index that
every PlayerSession stamps at join time and that /api/stream and
/api/intent both route by, handing a player somebody else's railroad with
no error anywhere.

And it fixed a live balance bug: minCombinedRevenue is derived from the
player count, but the config was fixed at CREATE while the count wasn't
known until START, so the lobby guessed 4. Every 2-player game ran against
a floor of 60 instead of 30 — and missing the floor means everyone loses,
so a 2-player competitive game was set up to fail for a UI artifact rather
than a rule.

/api/health gained games:{active,lobby}, read from a new cheap summary()
on GameSession rather than exportSave(), which would copy every intent of
every game to answer a question about none of them. Three admin routes are
new behind an ADMIN_SECRET env var in an x-admin-secret header: GET
/api/games, GET /api/games/<id>/save, DELETE /api/games/<id>. Until now a
started game could not be ended by anyone — no route, no player action, no
resignation — so an abandoned game stayed active in the index and was
faithfully resumed on every boot, forever.

Three deliberate choices there: the admin secret is NOT the join secret,
which every player holds and which would therefore let anyone at the table
destroy anyone else's game; unset means the routes 404 exactly as any
unknown path does, with or without a header, so a server never given an
administrator doesn't advertise that it has one; and a delete returns the
deleted game's save, since the intents are the game (D5) — nothing is
destroyed without being handed to whoever destroyed it.

SavedGame gained an optional lastMoveAt (falling back to createdAt) so
"has this stalled?" survives a restart. Kept out of history for the same
reason the turn timings are: a replay must reproduce a game from decisions
alone, and wall-clock is not a decision.

index.ts logs "Resuming N saved games..." before the loop rather than one
line per game after it. Measured a full 4-player game at 100ms to replay,
and only unfinished games are replayed, so listening before loading would
have bought nothing for the cost of a "still loading" state everywhere.

Verified: 667 tests pass (662 + 5), and the new session tests were checked
against two mutations (lastMoveAt never advancing; resume dropping it) to
confirm they fail without the code. Live against a running server: health
counts tracking through the lobby->game transition, admin auth rejecting a
missing and a wrong secret, list/export/delete, the deleted game's files
and index entry actually gone from disk, a second delete 404ing, the admin
routes invisible when ADMIN_SECRET is unset, and a 3-player table refusing
a 4th player and a size of 5 refused at the door.

Also carries the TODO items raised on 2026-08-21: the lobby offering no
game parameters (the floor bug within it now fixed, the form still
missing), and the four optionalRules — of which only reducedVisibility and
emergencyToolbox are read by anything, while sisterTrains and
employeeRotation are declared, defaulted, and consulted nowhere.

docs/architecture/multiplayer.md

@@ -245,7 +245,10 @@ special handling: `pump` stops, and the next push simply carries a `Menu` contai
 POST /api/lobby/create, /api/lobby/join      lobby
 POST /api/intent          { gameId, seq, intent }
 GET  /api/stream          EventSource — per-seat frames, with Last-Event-ID resume
-GET  /api/health          { ok, service, engineVersion } — unauthenticated; see below
+GET  /api/health          { ok, service, engineVersion, games } — unauthenticated; see below
+GET  /api/games           every game and lobby, summarised          ┐
+GET  /api/games/<id>/save the save, for keeping or replaying        ├ ADMIN_SECRET
+DELETE /api/games/<id>    ends a game, and returns its save         ┘
 GET  /                    the client
 ```
 
@@ -253,7 +256,19 @@ GET  /                    the client
 `dist/` is served both ways and the bundle is identical (D4), and every other route 404s an unknown
 path exactly as a static host does — so the splash asks, and closes its multiplayer door only when
 nothing names itself in reply. It is unauthenticated on purpose: it reveals that a Station Master
-server is answering and nothing else, no game and no seat.
+server is answering and nothing else, no game and no seat. Its `games` field — `{ active, lobby }`
+— is what the StartOS package's health check reports as "3 games in progress".
+
+**The three administrative routes are gated by `ADMIN_SECRET`, which is deliberately not the join
+secret.** Every player holds the join secret, so gating a delete with it would let anyone at the
+table destroy anyone else's game; this one belongs to whoever runs the server. It arrives in an
+`x-admin-secret` header rather than the query string, so it stays out of logs and referrers. When
+the variable is unset the routes answer 404 exactly as any unknown path does, so a server that was
+never given an administrator does not advertise that it has one.
+
+**A delete returns the deleted game's save.** The intents are the game (D5), so what comes back is
+the whole thing and not a summary of it — the record survives even though the game does not, and
+nothing is destroyed without being handed to whoever destroyed it first.
 
 Chosen over WebSocket because this game is **idle most of the time** — turn-based with human
 think-time means a connection sits silent for minutes, exactly when proxies reap sockets. SSE's