Based on Shinkai’s own novel of the same name and reframing his usual fixations through the lens of Japanese history, “Your Name” is an unclassifiable experience that starts like a hormonal riff on “Freaky Friday,” morphs into an apocalyptic version of “Portrait of Jennie,” and somehow manages to layer a gender-swapping 12th century tale over the ongoing trauma of 3/11 in the meantime.