When viewing a kind 1111 comment that replies to an addressable event
like a vine (34236), music, or article, the detail page now shows a
rich preview banner with thumbnail, kind label, title, and author —
matching the existing pattern for URL, profile, and community previews.
Works generically for all addressable event kinds by looking up the
kind label from EXTRA_KINDS and extracting thumbnails from image/imeta
tags.
Closes#75
Mary Kate Fain
b401a21cbc