- Add Service struct with db and logger dependencies and NewService constructor
- Add CreateDSR, GetDSR, ListDSRs, and ProcessDSR methods for data subject request lifecycle management
- Add processAccessRequest, processErasureRequest, processRectificationRequest, and calculateDueDate helper methods
- Add RecordConsent, RevokeConsent, and GetConsents methods for consent management
- Add LogAudit