A 28-year-old male farmer from rural Maharashtra presents with a 6-week history of progressive itching and scaling on his feet. On examination, he has erythematous, scaly patches with a characteristic 'moccasin' distribution involving the sole, lateral border, and heel of both feet. The toenails appear normal. KOH mount from scale shows septate hyphae. He has tried multiple topical antifungals without improvement. What is the most likely diagnosis?