adding classification and division yard updates, train collisions, engine and car updates, turnout improvements.

src/engine/setup.ts

@@ -196,6 +196,13 @@ function buildDivision(players: number, rng: Rng): DivisionNode[] {
     // least deterministic and varies between games; it should become a real player choice when
     // setup gains an interactive phase. See implications.md §10 Q11.
     if (mainlineProfile(card).speed.kind === 'grade') {
+      /**
+       * TEMPORARY, and flagged in TODO. The card prints "(Up)" and "Player sets orientation", so
+       * which way a Heavy Grade climbs is the player's decision — but it is dealt during setup, and
+       * setup has no decision point at all. Rolled from the seed until it gains one, because the
+       * orientation MATTERS: it decides which direction climbs, and therefore what a Brakeman or
+       * Helpers card is worth.
+       */
       node.gradeUp = rng.nextInt(2) === 0 ? 'east' : 'west';
     }
     return node;