A 28-year-old female presents with edema, fatigue, and foamy urine for the past 2 months. She has a history of systemic lupus erythematosus (SLE) diagnosed 3 years ago. Laboratory tests reveal nephrotic-range proteinuria (4.5 g/day), hypoalbuminemia, and elevated serum creatinine. Urinalysis shows no hematuria or cellular casts. Question:Which of the following is the most likely diagnosis?
