Delete a partner.
This API endpoint allows to delete a partner by its code.

Permanently removes a partner entity from the system using the unique partner code.
Validates that the partner code is provided and not empty before processing deletion.
Performs deletion operation directly through the repository interface.
May trigger cascade operations to handle related data such as member associations and onboarding records.
Returns confirmation of successful deletion with the partner code for audit purposes.
Consider implementing CQRS pattern for better separation of concerns and event sourcing.
Note: Current implementation uses direct repository deletion - consider adding domain events for audit trail.
Important: Deletion may impact associated member records and should be handled carefully.