make turnout description more clear. fix curves from breaking running track.

src/engine/apply.ts

@@ -50,6 +50,7 @@ import type { Occupancy, Port } from './track.ts';
 import {
   canDropCarsAt,
   canPlaceAt,
+  carriesThroughTrack,
   facilityVariants,
   opposite,
   reachableDestinations,
@@ -590,6 +591,11 @@ function checkPlay(
       {
         const proto = protoCard(card.kind, variant);
         if (!proto) return 'NO_PLACEMENT';
+        // Said separately from NOT_CONNECTED because it is a different mistake: the card would join
+        // perfectly well, and would still leave the Running Track stopping dead at it.
+        if (placement.row === area.runningRow && !carriesThroughTrack(proto)) {
+          return 'BREAKS_RUNNING_TRACK';
+        }
         return canPlaceAt(area, placement, proto) ? null : 'NOT_CONNECTED';
       }