Match the reference layouts for the remaining forum routes: plate pages
get the blurred header card, moderator row and the affix tab bar with
per-tab filtering, topping posts and moderator-only pending/trash tabs;
post pages get the article shell with breadcrumbs, cover, meta row,
vote box, tag row and footer actions; compose pages get the reference
editor plus settings sidebar (submit/draft, status, access, plate,
topic, tag, type, vote) with a cover picker. Saving now honours draft
state and the featured image through the REST contract.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>