A 35-year-old man with HIV (CD4 count 45 cells/μL) presents with progressive dysphagia and retrosternal chest pain for 2 weeks. Endoscopy reveals multiple ulcers with white plaques in the esophagus. Biopsy shows cytopathic effect with intranuclear and intracytoplasmic inclusion bodies. Which herpesvirus is most likely responsible, and what is the mechanism of mucosal damage?