Implement Enhancements, Mainline modifiers and Maneuvers; fix unplayable track

src/engine/intents.ts

@@ -4,7 +4,7 @@
  * An intent is a PROPOSAL. It may be rejected. Contrast with an event (events.ts), which is a fact.
  */
 
-import type { CarType, Direction, OfficeTier } from './content.ts';
+import type { CarType, Direction, Hand, OfficeTier, TrackGeometry } from './content.ts';
 import type { CardId, GridCoord, PlayerIndex, TrayId } from './state.ts';
 
 // ---------------------------------------------------------------------------
@@ -18,6 +18,12 @@ export type Intent =
   // -- switch (§6.1, Appendix A)
   | { type: 'switch.move'; trayId: TrayId; to: GridCoord; reverse: boolean }
   | { type: 'switch.dropCars'; trayId: TrayId; count: number }
+  /**
+   * Small Yard enhancement — "a train that spends one move in the yard may sort itself in any
+   * order, including cars in front of the engine". This is the designed answer to §A.3's
+   * come-off-in-seated-order constraint, which is what makes facing-point work possible.
+   */
+  | { type: 'switch.sortConsist'; trayId: TrayId; order: number[] }
   | { type: 'switch.end' }
   // -- draw (§6.2)
   | { type: 'draw.fromHomeOffice' }
@@ -25,6 +31,14 @@ export type Intent =
   /** `variant` indexes `variantsFor(geometry)` — Gap 11: orientation is chosen on placement. */
   | { type: 'card.play'; cardId: CardId; placement?: GridCoord; variant?: number }
   | { type: 'card.discard'; cardId: CardId; toSlot: number }
+  /**
+   * Lay a piece from your personal track supply (§12.2 / content.ts TRACK_SUPPLY).
+   *
+   * ASSUMPTION, flagged: the design moves track out of the deck into a per-player supply but does
+   * not say when you may lay it. Treated as a play available during the "draw a card" option,
+   * matching how track behaved when it WAS a card. See implications.md §10 Q10.
+   */
+  | { type: 'track.lay'; geometry: TrackGeometry; hand: Hand; placement: GridCoord; variant?: number }
   | { type: 'draw.end' }
   // -- freight agent (§6.3)
   | { type: 'freightAgent.stockOutbound'; at: GridCoord; carType: CarType }
@@ -37,6 +51,21 @@ export type Intent =
   | { type: 'newTrain.secondSection'; trainNumber: number }
   // -- Mainline Phase (§8.1) — the Superintendent's clearance ruling
   | { type: 'mainline.clearance'; allow: boolean }
+  /**
+   * Lay a Mainline modifier (Brakeman / Airbrakes / Helpers / Realignment) on a Mainline card.
+   * `node` indexes `division.nodes`.
+   */
+  | { type: 'mainline.modify'; cardId: CardId; node: number }
+  /**
+   * Red Flags — protect a stopped train. The flagged train cannot be hit; an approaching train is
+   * held instead of colliding.
+   */
+  | { type: 'maneuver.redFlags'; cardId: CardId; trayId: TrayId }
+  /**
+   * Flying Switch — cut cars off behind the engine and roll them into an adjacent industry, without
+   * the engine entering it.
+   */
+  | { type: 'maneuver.flyingSwitch'; cardId: CardId; trayId: TrayId; count: number; to: GridCoord }
   | { type: 'redFlag.play' }
   // -- Load/Unload Phase (§9)
   | { type: 'porter.board'; at: GridCoord }
@@ -83,6 +112,10 @@ export type RejectionCode =
   | 'NOT_UPGRADEABLE'
   | 'FACILITY_LOCKED'
   | 'NOT_IMPLEMENTED'
+  | 'WRONG_INTENT'
+  | 'NOT_A_GRADE'
+  | 'TRAIN_ON_CARD'
+  | 'CONSIST_ORDER'
   | 'NO_TRAIN_AT_OFFICE';
 
 export type Rejection = { code: RejectionCode; message: string };