feat: P15 ending gallery, chapter recap, visited tracking, save system v6

engine/types.ts

@@ -88,12 +88,20 @@ export interface AchievementDef {
   condition: Condition
 }
 
+export interface EndingDef {
+  id: string
+  label: string
+  sceneId: string
+  thumbnail?: string
+}
+
 export interface GameData {
   scenes: Record<string, SceneNode>
   startScene: string
   variables: Record<string, number>
   chapters?: ChapterInfo[]
   achievements?: AchievementDef[]
+  endings?: EndingDef[]
 }
 
 export interface ChoiceRecord {