post https://example.com/os/v1/positions
Creates a new position with the provided data.
Business Rules:
• Role (externalCodeRole) is required and must exist
• Area (externalCodeArea) is required and must exist
• External code must be unique within the company
• Parent position is optional - if not specified, creates a root position
• Only one root position allowed per company
• Employee can only be assigned to one position at a time
• Employee assignment is optional (position can be vacant)
• Operation Unit (externalCodeOperationUnit) is optional - if provided, must exist