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/components/HeaderBand/variants.ts

@@ -0,0 +1,25 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+import { tv } from "tailwind-variants/lite";
+
+// The white header band that sits over the grey body: full-width surface with a
+// bottom border and a centered max-w-5xl content column. Shared by the landing
+// Hero and the page headers so the band is defined once.
+export const headerBand = tv({
+  slots: {
+    band: "flex w-full flex-col items-center border-b border-sand-6 bg-sand-1 px-8 py-8",
+    inner: "w-full max-w-5xl",
+  },
+});