MILAN — At the very end of the Prada show on Thursday, the audience witnessed one of those symbolic moments whose weight will only be truly felt with the passage of time. Fabio Zambernardi, who has been Miuccia Prada’s right hand for nigh on thirty years, entered stage left to take a public bow for the first time with Miuccia, along with her co-designer Raf Simons. Watching that moment, it was hard not to think that the collection we’d…