A 35-year-old man presents to the emergency department with a 3-day history of fever, severe headache, and progressive confusion. On examination, he has altered mental status, dysphasia, and complex partial seizures. MRI brain shows T2/FLAIR hyperintensity in the left mesial temporal lobe with hemorrhage. An EEG is performed and shows the pattern marked **A** in the diagram — periodic lateralized epileptiform discharges over the temporal lobe at 1–2 second intervals. CSF analysis reveals lymphocytic pleocytosis with elevated protein and normal glucose. Based on this clinical presentation and EEG finding, which of the following is the most likely diagnosis and the pathophysiological basis of the temporal lobe involvement?