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

src/sim/replay.ts

@@ -202,9 +202,9 @@ export function compress(frames: Frame[]): Packed {
       // Identity, not equality: `snapshot` pushes the very same FacilityView object into both the
       // cell and the frame's `facilities`, so this always resolves.
       const fi = c.facility ? f.facilities.indexOf(c.facility) : -1;
-      // `train` rides whole rather than being interned: it changes almost every frame, so a table
+      // `trains` rides whole rather than being interned: it changes almost every frame, so a table
       // of them would be as long as the frames are and buy nothing.
-      return [ci, wi, c.enhancements, c.tray, c.cars, fi, c.train, c.ad, c.enhancementsWhat, c.standingWest];
+      return [ci, wi, c.enhancements, c.cars, fi, c.trains, c.adTracks, c.enhancementsWhat, c.standingWest];
     });
     return { ...f, cells } as unknown as Frame;
   });
@@ -238,21 +238,26 @@ export function rehydrateCells(
   facs: unknown[],
 ): unknown[] {
   return packed.map((row) => {
-    const p = row as [number, number, string[], string | null, string[], number, unknown, unknown, string[], number];
+    const p = row as [number, number, string[], string[], number, unknown, unknown, string[], number];
     const c = cards[p[0]] as [number, number, string, string, boolean, string[]];
+    // Tolerant the same way `standingWest` below is: an array rides through as-is, a lone object
+    // (an older recording's singular `train`) is wrapped into a one-train roster, and null or
+    // undefined reads as no train at all.
+    const rawTrains = p[5];
+    const trains = Array.isArray(rawTrains) ? rawTrains : rawTrains ? [rawTrains] : [];
     return {
       row: c[0], col: c[1], kind: c[2], label: c[3], running: c[4], links: c[5],
-      what: whats[p[1]], enhancements: p[2], tray: p[3], cars: p[4],
-      facility: p[5] < 0 ? null : facs[p[5]],
-      train: p[6] ?? null,
-      ad: p[7] ?? null,
+      what: whats[p[1]], enhancements: p[2], cars: p[3],
+      facility: p[4] < 0 ? null : facs[p[4]],
+      trains,
+      adTracks: (p[6] as number | undefined) ?? null,
       // Carried rather than recomputed: this function is emitted into the page by toString() and so
       // cannot reach the card catalogue that produced the text.
-      enhancementsWhat: p[8] ?? [],
-      // Where the train on this card stands among the cars standing on it, so the replay draws a cut
-      // ahead of or behind the engine exactly as the live board does. Absent in older recordings,
+      enhancementsWhat: p[7] ?? [],
+      // Where the train(s) on this card stand among the cars standing on it, so the replay draws a
+      // cut ahead of or behind the engine exactly as the live board does. Absent in older recordings,
       // which read as 0 — the whole cut east of the engine, which is what they used to draw anyway.
-      standingWest: p[9] ?? 0,
+      standingWest: p[8] ?? 0,
     };
   });
 }