Optimal Follow‑Up Timing and Assessment After a 6‑Week Terbinafine Course for Fingernail OnychomycosisTiming of Follow‑UpAssessment Criteria at the 18‑Week VisitEarly Monitoring When Clinically IndicatedManagement of Persistent Mycological PositivityCommon Pitfalls to AvoidComparative Efficacy Guidance (British Association of Dermatologists)