Remove NewBook room blocking — app never writes to NewBook

Unsellable flag is in-app visibility only; staff mark rooms out of
order in NewBook through their own process. NewBook use is now
read-only (room sync + occupancy filter).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/pages/Summary.tsx

@@ -115,7 +115,6 @@ export default function Summary() {
             <div className="task-card-title">
               {t.title}
               {t.unusable && <UnusableBadge />}
-              {t.newbook_blocked && <span className="badge badge-outline">NB blocked</span>}
               {t.template_id && <span className="badge badge-outline">Recurring</span>}
             </div>
             <div className="task-card-meta">