Feature Request: Add Button and API to Duplicate Shipments

[jacobshilitz]

Is your feature request related to a problem? Please describe.
Duplicating a shipment manually is time-consuming and error-prone, especially during development when consistent test data is needed.

Describe the solution you'd like
Add a button in the UI and an API endpoint to duplicate a shipment. This should copy all details from the existing shipment to create a new one.

Describe alternatives you've considered
Currently, I use a saved API request to manually duplicate shipments. This is functional but not as efficient or user-friendly as an integrated feature.

Additional context
This feature would help streamline the shipping process and be beneficial for development and testing.