A 5-yeаr-оld child is brоught tо the clinic with fever, worsening left eаr pаin, and swelling behind the ear. The parent reports the child was diagnosed with acute otitis media 1 week ago but did not complete the prescribed antibiotics. Physical examination reveals erythema, tenderness, and swelling over the left mastoid process with protrusion of the auricle outward and downward. Which of the following is the most likely diagnosis?