v0.3.0 — playtest fixes, two new rules, and §7 enforced

src/engine/legal.ts

@@ -156,7 +156,22 @@ function localOpsCandidates(s: GameState, player: PlayerIndex): Intent[] {
         out.push({ type: 'card.play', cardId, node });
       }
     }
-    const targets = onMainline ? [] : kind?.kind === 'enhancement' ? attachments : placements;
+    /**
+     * A TURNOUT MAY ALSO UPGRADE A CARD ALREADY DOWN, so it is offered the occupied cells as well as
+     * the empty ones — `check` decides which of them it can actually be laid over. Without this the
+     * upgrade rule exists in the engine and is never once presented, which is precisely how the 18
+     * Enhancement cards came to be permanently dead.
+     *
+     * Deduplicated because the two lists overlap: `placements` already contains the Limits signs.
+     */
+    const isTurnout = kind?.kind === 'track' && kind.geometry === 'turnout';
+    const targets = onMainline
+      ? []
+      : kind?.kind === 'enhancement'
+        ? attachments
+        : isTurnout
+          ? dedupe([...placements, ...attachments])
+          : placements;
     // Orientation is chosen on placement, and a printed card turns but never flips, so the widest
     // variant set is TWO. Anything that is not track has a single orientation and needs one entry.
     const rotations = kind?.kind === 'track' ? variantsFor(kind.geometry, kind.hand).length : 1;
@@ -226,7 +241,8 @@ function loadUnloadCandidates(s: GameState, player: PlayerIndex): Intent[] {
     const f = area.grid.get(`${coord.row},${coord.col}`)?.facility;
     if (f) {
       out.push({ type: 'laborer.startLoad', at: coord });
-      for (let box = 0; box < f.menAtWork.length; box++) {
+      // A Passenger Facility has no MEN | AT | WORK boxes to advance a load along.
+      for (let box = 0; box < (f.menAtWork?.length ?? 0); box++) {
         out.push({ type: 'laborer.advanceLoad', at: coord, box });
       }
       for (let ci = 0; ci < f.industryTrack.cars.length; ci++) {
@@ -248,6 +264,16 @@ function facilityCoords(s: GameState, player: PlayerIndex): GridCoord[] {
   return out;
 }
 
+function dedupe(coords: GridCoord[]): GridCoord[] {
+  const seen = new Set<string>();
+  return coords.filter((c) => {
+    const k = `${c.row},${c.col}`;
+    if (seen.has(k)) return false;
+    seen.add(k);
+    return true;
+  });
+}
+
 /** Empty cells adjacent to occupied ones — `check` decides which actually connect. */
 function placementCandidates(s: GameState, player: PlayerIndex): GridCoord[] {
   const area = areaOf(s, player);