feat: chapter select system, multi-chapter support, scene manager refactor, and docs update

engine/systems/SaveSystem.ts

@@ -12,13 +12,19 @@ interface SaveRecord {
   thumbnail?: string
 }
 
+interface UnlockRecord {
+  chapterId: string
+}
+
 class SaveDB extends Dexie {
   saves!: Table<SaveRecord, number>
+  unlocks!: Table<UnlockRecord, string>
 
   constructor() {
     super('MovieGameSaves')
-    this.version(2).stores({
+    this.version(3).stores({
       saves: '++id, slot',
+      unlocks: 'chapterId',
     })
   }
 }
@@ -73,4 +79,21 @@ export class SaveSystem {
   async delete(slot: number): Promise<void> {
     await db.saves.where('slot').equals(slot).delete()
   }
+
+  async unlockChapter(chapterId: string) {
+    const exists = await db.unlocks.get(chapterId)
+    if (!exists) {
+      await db.unlocks.put({ chapterId })
+    }
+  }
+
+  async isChapterUnlocked(chapterId: string): Promise<boolean> {
+    const record = await db.unlocks.get(chapterId)
+    return !!record
+  }
+
+  async getUnlockedChapters(): Promise<string[]> {
+    const records = await db.unlocks.toArray()
+    return records.map((r) => r.chapterId)
+  }
 }