Remove TTS narration and improve BGM

src/game/scenes/StoryScene.ts

@@ -116,7 +116,6 @@ export class StoryScene extends Phaser.Scene {
 
   private applyPage(page: StoryPage) {
     soundDirector.playMusic(page.bgm);
-    soundDirector.playVoice(page.voice, page.voiceRole ?? page.portrait ?? 'narrator');
     this.applyBackground(page.background);
     this.chapterText?.setText(page.chapter);