feat: Implement segment update and regeneration features in Audiobook API and frontend

qwen3-tts-frontend/src/locales/ko-KR/audiobook.json

@@ -114,7 +114,16 @@
 
     "segments": {
       "errorBadge": "오류",
-      "unknownCharacter": "?"
+      "unknownCharacter": "?",
+      "edit": "편집",
+      "save": "저장",
+      "cancel": "취소",
+      "regenerate": "재생성",
+      "regenerating": "생성 중...",
+      "savedSuccess": "세그먼트가 저장되었습니다",
+      "emotion": "감정",
+      "noEmotion": "감정 없음",
+      "intensity": "강도"
     },
 
     "sequential": {