v0.7.3 — a game that asks before it ends, and a results screen worth reading

Two issues off the tracker, and they are halves of one thing: the end of a game.
Neither ships on the 0.4.9 line — Jesse's call, that line may be complete and
these are not fixes people mid-playtest need.

EXTENDED PLAY (#11). The official result is settled at the original game length
and never changes: in a five-Day game extended to eight, the winner is whoever
led at the end of Day 5. Extending grants exactly one Day and the question is put
again at the end of it — solitaire the player decides alone, multiplayer it is
unanimous and one refusal ends it there. Only days-based endings offer it; a §3.4
collision breach is final, during an extended Day exactly as during the scheduled
game.

It could not be a client-side change. `check` refused every intent once `status`
left `active`; the server never loads a `finished` game back into memory; and a
save is `{ seed, config, history }` replayed through the engine, so a "continue"
the history does not record did not happen. Hence a fourth status,
`awaitingExtension`, and a `game.extend` intent. `config.days` never moves —
`extraDays` counts the borrowed Days and `official` freezes the outcome, the
standings and the statistics at the first ending.

THE RESULTS SCREEN (#16). `GAME OVER — revenueFloor` was `outcome.reason`, an
internal enum interpolated into the page at the one moment the game has the
player's whole attention. Every reason now has a sentence with the game's own
numbers in it. Around it: the result and winner, standings, the rules the game
was dealt under, a per-player breakdown, and the railroad — trains through the
Division and how many worked en route, loads made up and broken, passengers, cars
switched, trains destroyed. It shares the Day-end dialog's blocks rather than
reimplementing them, and stays reopenable so continuing does not cost you the
results.

Statistics are folded, not recorded: `state.tally` counts what the event stream
says happened, hooked at `applyIntent` and `advance` because `reduce` never sees
the phase driver's events — and those are the interesting ones. Nothing in the
rules reads it, and it rides the Frame, so multiplayer gets the same numbers as
solitaire from one implementation.

THREE BUGS FOUND IN TESTING, all of which would have shipped:

  - a saved game containing a vote could not be resumed (NO_ACTOR). A history is
    a flat Intent[] with no seat recorded; the replay derives who acted from the
    turn order, which cannot work for an intent every seat may send in any order.
    `game.extend` carries its voter, checked against the authenticated seat.
  - an all-bot game hung on the question for ever. `driveBots` loops on
    `currentActor`, null the moment the game stops, so it cannot cast a vote, and
    the bot-vote driver returned early with no humans to follow.
  - the balance harness became unbounded — `test/sim.test.ts` went from under a
    second to never finishing. `randomBot` took another Day about half the time,
    so every seeded game ran to playGame's 50,000-turn cap. Fixed in the driver,
    not in a policy, so it holds for bots not yet written.

All three have regression tests. 832 tests pass, against 793 before this change.

NOT BUILT, and a correction. #16's own comment said `trainStoodStill` "is emitted
per Stage, so a run of them is exactly the sat-on-a-siding streak". It is not:
reading advance.ts, it fires once per game and only for a train whose profile
sets `stopEarnsPoint` — the X18 Circus — with `stopPointClaimed` preventing a
second. The streak was built, rendered "1 Stage at (0,0)", and was taken out
again. There is no per-Stage "this train did not move" signal in the engine, so
"longest an engine sat on a siding" needs one first; TODO.md #36 records what it
would take, and the Circus set-up is reported instead. Badges remain the second
pass #16 asks for (TODO.md #33), and because the statistics are derived rather
than recorded, that pass can add any of them retroactively to games already
played and saved.

Extended play has not yet been played at a real table (TODO.md #35): the
multiplayer vote has only been driven through `session.intent`, never through two
browsers.

Closes #11
Closes #16

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EAgJSmeV8zrMh55Mj85ESb

README.md

@@ -132,6 +132,25 @@ is the thing this machinery exists to prevent.
   roughly a third of the event types are never reduced at all. Anything that needs to rebuild a game
   replays the intents.
 - **Never call `Math.random()`.** One ambient random call silently breaks replay.
+- **A game ends by PAUSING, and the first ending is the real one.** Running out of Days, or closing
+  short of the combined Revenue floor, puts the game in `awaitingExtension` rather than `finished`:
+  the table is asked whether to play one more Day, unanimously, and asked again at the end of every
+  Day it grants. `state.official` is written at the first ending and never rewritten, so the winner
+  is always the one decided at `config.days` however long play carries on — `config.days` itself
+  never moves, and `state.extraDays` counts the borrowed ones. A §3.4 collision breach is the
+  exception and finishes outright, during an extended Day exactly as during the scheduled game.
+  Because a save is a replay, the vote is an intent (`game.extend`), and it is the one intent that
+  **carries its own player**: every seat may vote in any order, so a replay cannot derive who did.
+- **Statistics are folded, not recorded.** `state.tally` counts what the event stream says happened —
+  trains through the Division and how many of them did any switching, loads made up and broken — and
+  is hooked
+  at the two boundaries every event crosses exactly once, `applyIntent` and `advance`. It is not
+  hooked in `reduce`, which never sees the phase driver's events at all. Nothing in the rules reads
+  it, so adding a counter is always safe; it rides the `Frame`, so a multiplayer client gets the same
+  numbers as solitaire from one implementation. **What it cannot count is anything the events do not
+  say.** `trainStoodStill` fires once per game for the X18 Circus alone, so "the longest an engine sat
+  on a siding" has no signal behind it — see `TODO.md` #36 rather than assuming an event means what
+  its name suggests.
 - **A game is one of four TYPES, and a type is a set of defaults rather than a ruleset.** Co-op,
   Competitive, Cutthroat and Solitaire (`src/web/presets.ts`) each name an opening hand, an Extra
   rule, three revenue rates and the victory conditions; picking one fills the form, and changing any