VSN-1999 : Refactoring multiple saving process of passengers in preparation first phase.

Merge Request Description

Overview

This merge request introduces a comprehensive refactoring of the passenger preparation process.
The primary objective is to improve reliability, transparency, and scalability during the initial saving operations.

Key Enhancements

• Saving Status Tracking
  A new indicator has been implemented to distinguish between passengers who were already saved and those newly added.
  This provides greater clarity in monitoring preparation progress.

• Data Consistency Improvements
  The mapping between circuit codes and UUIDs has been corrected to ensure accurate data handling.
  This adjustment strengthens the integrity of the preparation workflow.

• Utility Methods for Bulk Operations
  New methods such as saveAll and mapToEntity have been introduced.
  These utilities streamline mass importation of prepared passengers and reduce redundancy in service logic.

Service Layer Improvements

The service layer has been expanded to support bulk importation of prepared passengers.
This enhancement improves scalability, simplifies implementation, and ensures smoother integration with other system components.

Controller Updates

New features have been exposed through the controller, making them accessible for integration and testing.
This ensures that the preparation workflow aligns with broader system requirements and facilitates validation of new functionalities.

Impact

These changes collectively strengthen the robustness of the preparation service.
They minimize potential errors in passenger data handling, improve transparency in saving operations, and establish a solid foundation for more efficient mass operations in future development phases.

Closes VSN-1999