feat(mystery): sample 3-room world for engine validation

src/world/index.ts

@@ -0,0 +1,14 @@
+import type { World } from './types'
+import { rooms } from './rooms'
+import { items } from './items'
+import { encounters } from './encounters'
+import { endings } from './story'
+
+export const world: World = {
+  startingRoom: 'foyer',
+  startingInventory: ['matches'],
+  rooms,
+  items,
+  encounters,
+  endings,
+}