A 28-year-old woman presents to the emergency department with severe sore throat, odynophagia, and fever (39.5°C) for 3 days. On examination, she has unilateral tonsillar enlargement with exudate, uvula deviation to the left, trismus, and a 'hot potato' voice. Intraoral palpation reveals a bulge in the soft palate above the tonsil. Her white cell count is 14,500/μL. What is the most likely diagnosis?