feat: add segment tracking to audiobook projects and update UI to display progress

qwen3-tts-backend/schemas/audiobook.py

@@ -45,6 +45,8 @@ class AudiobookProjectResponse(BaseModel):
     script_config: Optional[Dict[str, Any]] = None
     created_at: datetime
     updated_at: datetime
+    segment_total: int = 0
+    segment_done: int = 0
 
     model_config = ConfigDict(from_attributes=True)