feat: v0.8.0 — player-actions API: accept/dispatch/buy/sell/refuel endpoints (tick-first, full-snapshot responses), spawn coverage rule, test create-contract hook

lib/game/catalog.ts

@@ -10,6 +10,9 @@ export interface PlaneType {
   burnPerKm: number;
   // Cruise speed, km/h — used by the sim tick to advance planes along routes.
   speedKmh: number;
+  // Market price in € (v0.8.0): buying costs `price`, selling pays out
+  // SELL_FRACTION × price.
+  price: number;
 }
 
 export const PLANE_TYPES: Record<string, PlaneType> = {
@@ -19,8 +22,17 @@ export const PLANE_TYPES: Record<string, PlaneType> = {
     maxFuel: 6300,
     burnPerKm: 1.75, // ~900 kg/h at 510 km/h cruise (Jet-A1 ≈ 0.8 kg/L)
     speedKmh: 510,
+    // €200k — with the starting cash of €20k and typical hop rewards (~€1–3k),
+    // a second ATR takes sustained play to afford, as intended for the MVP sink.
+    price: 200_000,
   },
 };
 
 // The plane the player starts with.
 export const STARTER_MODEL = 'atr72';
+
+// Jet-A1 fuel price in €/liter (v0.8.0): refueling cost = (maxFuel − fuel) × this.
+export const FUEL_PRICE_PER_L = 0.8;
+
+// Fraction of the catalog price paid out when selling a plane (v0.8.0).
+export const SELL_FRACTION = 0.5;