Adapt + improve all public pages to the atom design system

Extended the same design-system treatment to the public site, faithful
to AtomCMS's "atom" theme. New src/components/public/ui.tsx provides the
signature atom building blocks + a scoped CSS layer:
- ContentCard: surface card with a primary-tinted header (icon circle +
  title + subtitle) and padded body — the atom content-card, used as
  every page's header and section wrapper.
- StatBlock / stat-grid, EmptyState, OnlineBadge (online/offline pill),
  RankBadge (medals for the top 3), and responsive .card-grid helpers.

Swept ~45 public pages (home/community/rankings hand-built as the
reference; the rest via parallel agents that read the schema and
preserved every query, server action, auth gate and field name):
heroes → ContentCard headers, lists → card-grids in ContentCards,
"no X" → EmptyState, status → OnlineBadge/RankBadge. The leaderboard
gained Credits/Diamonds/Duckets tabs (usersCurrency).

Behaviour unchanged. Verified on the prod server against amx_test: 15+
public pages render the content-cards/grids with real data, no errors;
computed styles confirm the tinted header, icon circle, medal + online
pills. Fixed an undefined --color-golden ref. tsc 0, vitest 49/49,
next build 0.

src/app/client/page.tsx

@@ -1,5 +1,6 @@
 import { headers } from "next/headers";
 import { redirect } from "next/navigation";
+import { ContentCard, EmptyState } from "@/components/public/ui";
 import { issueSsoTicket } from "@/lib/auth/sso-ticket";
 import { auth } from "@/lib/auth";
 import { prisma } from "@/lib/prisma";
@@ -30,19 +31,28 @@ export default async function ClientPage() {
     : "";
 
   return (
-    <main>
-      <h1>Launching {hotelName ?? "Atom"}…</h1>
+    <main style={{ display: "grid", gap: "1.5rem" }}>
+      <ContentCard
+        icon="🏨"
+        title={`Launching ${hotelName ?? "Atom"}…`}
+        subtitle="Your single sign-on ticket is ready"
+      />
+
       {src ? (
-        <iframe
-          title="Hotel client"
-          src={src}
-          style={{ width: "100%", height: "80vh", border: 0, borderRadius: 10 }}
-        />
+        <ContentCard padded={false}>
+          <iframe
+            title="Hotel client"
+            src={src}
+            style={{ width: "100%", height: "80vh", border: 0, borderRadius: 10, display: "block" }}
+          />
+        </ContentCard>
       ) : (
-        <p className="muted">
-          No client URL configured (set <code>nitro_client_url</code> in settings). SSO ticket
-          issued for this session: <code>{ticket}</code>
-        </p>
+        <ContentCard icon="🔌" title="No client configured" subtitle="Set nitro_client_url in settings">
+          <EmptyState icon="🔌">
+            No client URL configured (set <code>nitro_client_url</code> in settings). SSO ticket
+            issued for this session: <code>{ticket}</code>
+          </EmptyState>
+        </ContentCard>
       )}
     </main>
   );