Add Trust Center hero and page headers

Build the Trust Center landing hero and the nav page headers on a shared
HeaderBand shell. The home page loads its own query and feeds the Hero
(org headline, description, and contact info) via a colocated fragment;
the Documents, Subprocessors, Updates, and Data Requests pages use a
PageHeader (size-7 title, optional count, inline actions). Switch the
layout body to the grey sand-2 canvas so the white header bands read as
surfaces on top.

Split the header UI into focused components rather than one
over-configurable Hero: HeaderBand owns the band, Hero the landing
content, PageHeader the nav-page content. Add a hostname helper under
lib/url and standardize the 1024px container on the max-w-5xl token.

The Documents/Subprocessors filter/search/tabs toolbars and item counts
are deferred until the matching v2 components and queries exist.

Signed-off-by: Émile Ré <emile@probo.com>

apps/compliance-portal/src/pages/MainLayoutSkeleton.tsx

@@ -16,7 +16,7 @@ import { TopBarSkeleton } from "#/components/TopBar/TopBarSkeleton";
 
 export function MainLayoutSkeleton() {
   return (
-    <div className="min-h-screen bg-sand-1">
+    <div className="min-h-screen bg-sand-2">
       <TopBarSkeleton />
     </div>
   );