A 42-year-old woman with known chronic hepatitis B (HBeAg-positive, HBV DNA 10^6 copies/mL) on no antiviral therapy presents with acute onset jaundice, malaise, and right upper quadrant pain. She denies recent alcohol use or new medications. On examination: temperature 38.2°C, icteric, hepatomegaly (4 cm), no ascites, no splenomegaly. Laboratory findings: total bilirubin 9.5 mg/dL (direct 7.2 mg/dL), ALT 4200 IU/L, AST 3800 IU/L, ALP 220 IU/L, albumin 3.2 g/dL, PT-INR 1.8. Serologies: HBsAg positive, anti-HBc IgM positive, HBeAg positive, HBV DNA 8 × 10^6 copies/mL, anti-HAV IgM negative, anti-HCV negative. What is the most likely diagnosis?