the Roster Pass: every train at the Office visible

Builds "The Roster Pass" / "Two Trains, One Card" (station display for
multiple trains at one Office). The Office is the one square where
more than one train may legally stand at once (one per A/D track), and
CellView.train had room for exactly one — a second train at a busy
Station was counted in the old A/D pips and never drawn.

CellView.train -> CellView.trains: TrainView[], seat-filtered and
collecting every match rather than the first (fixes a latent
cross-district leak in the process: trainOnCard never checked seat).
The A/D pips are replaced with one roster chip per A/D track, always,
free or occupied; clicking a chip sets selectedCrew, wiring the board
and the action panel to the same value.

standingWest moves from CrewTray to TrackCard: two trays sharing one
Office card need one shared split, not one each, and there is no such
thing as "west of one particular A/D track". No save migration — Save
replays through the engine — and a stale value on an emptied card is
inert because nothing reads a split with no train standing there.

The Division map's Office cell is now sized by A/D capacity rather
than occupancy, so it holds still as trains arrive and leave; chips
lay into fixed slots instead of centre-spreading onto the Limits cards
either side.

584 tests, 0 failures. Verified end-to-end against the built app and a
direct render of a 4-train Terminal (screenshotted).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SAt2YCXgd5qCjBcF2x34aK

CHANGELOG.md

@@ -21,9 +21,10 @@ page as `v0.1.0 · <sha> · <date>`, so what is deployed can always be identifie
 
 ## 0.4.8 — 2026-08-19
 
-Three reports from the same game, all about squares: which ones a card may go on, which one a button
-in the action list means, and — when there is more than one legal road to the same square — which
-one a train actually takes.
+Four reports from the same game, all about squares: which ones a card may go on, which one a button
+in the action list means, when there is more than one legal road to the same square which one a
+train actually takes, and — when more than one train is standing at the same Office — which is
+which.
 
 ### The Limits bound the district, not just the Running Track
 
@@ -168,6 +169,46 @@ built a district where the discarded route would have mattered. 400 full games (
 ablation flag to run at all and this is not a bot heuristic, so paired A/B was not applicable here;
 the enumeration-based argument above is the actual evidence.
 
+### The Roster Pass — every train at the Office visible
+
+**The Office is the one square where more than one train may legally stand at once** — it has
+several A/D tracks, each holding one — and the board drew it as if only one ever could. Two trays
+at a Station couple onto the identical `officeCoord`; `trainOnCard()` returned on the first match
+and `CellView.train` had room for exactly one, so a second train was counted in the old A/D pips
+and never drawn at all. Reported directly, and analysed in "Two Trains, One Card": the pips and the
+picture were reading different fields.
+
+**`CellView.train` is now `CellView.trains: TrainView[]`** — every train standing on the card, each
+carrying its own `trayId`. The A/D pips are gone; in their place is one roster chip per A/D track,
+always (`adTracks` of them, not one per train), free tracks reading a dashed, dimmed "free" rather
+than vanishing. The selected train's chip is lit the same amber the crew strip and action buttons
+use, and its consist is the one drawn at the rail — clicking any occupied chip sets `selectedCrew`,
+the same value the "Which train are you switching?" picker already wrote, so the board and the
+action panel drive one value in both directions.
+
+**`standingWest` moved from `CrewTray` to `TrackCard`.** The split still means what it always meant
+— west/east of the row of standing cars — and it is still only meaningful while an engine stands on
+the card (an unattended cut has no near or far side; that reasoning did not change). What forced the
+move: two trays sharing one Office card could otherwise hold two different splits of the identical
+row, and there is no such thing as "west of one particular A/D track" — a cut lies west or east of
+the *whole block* of A/D tracks, so there has to be exactly one number for the card to carry. No
+save migration: `Save = {seed, history, rules?}` replays through the engine rather than being
+loaded, and a stale value on an emptied card is inert because nothing reads a split with no train
+standing there.
+
+**The Division map stopped drawing trains on their neighbours.** The Office's Running Track cell was
+a fixed 78px regardless of how many A/D tracks it had, so two chips centre-spread wider than the
+cell and spilled onto the Limits cards either side. The cell is now sized by **capacity**
+(`max(78, adTracks·54+12)`), not by how many tracks are occupied — sized by occupancy instead, the
+board would have shifted the East Division Point sideways every time a train arrived or left — and
+chips are laid into fixed slots, one per A/D track, so none can ever overhang the cell.
+
+**Verified:** two trays at a Station are both drawn, each with its own chip; a Terminal's four
+tracks all fit; a bare cut with a stale `standingWest` still draws left-aligned; every roster chip's
+x-extent lies inside its Office cell at full occupancy; and a packed replay row from before this
+feature — a lone train object, not an array — rehydrates into a one-train roster rather than
+throwing. 584 tests, 0 failures.
+
 ### Also
 
 - The three published replays were re-recorded. A save is a seed and its intents, so tightening a