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

qwen3-tts-backend/db/crud.py

@@ -640,6 +640,26 @@ def update_audiobook_segment_status(
     return seg
 
 
+def update_audiobook_segment(
+    db: Session,
+    segment_id: int,
+    text: str,
+    emo_text: Optional[str],
+    emo_alpha: Optional[float],
+) -> Optional[AudiobookSegment]:
+    seg = db.query(AudiobookSegment).filter(AudiobookSegment.id == segment_id).first()
+    if not seg:
+        return None
+    seg.text = text
+    seg.emo_text = emo_text or None
+    seg.emo_alpha = emo_alpha
+    seg.status = "pending"
+    seg.audio_path = None
+    db.commit()
+    db.refresh(seg)
+    return seg
+
+
 def delete_audiobook_segments(db: Session, project_id: int) -> None:
     db.query(AudiobookSegment).filter(AudiobookSegment.project_id == project_id).delete()
     db.commit()