- Rename Handler to MVNOHandler for clarity in handler_mvno.go
- Replace services.OnboardingService with OnboardingService interface for dependency injection
- Change monitor.OnboardingRequest, monitor.MVNOStatus, monitor.MVNOFilter, and monitor.MVNOPlan to mvno package types
- Remove monitor package import from handler_management.go and handler_mvno.go
- Add context.Context import for service method signatures