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/redeem/page.tsx

@@ -1,5 +1,6 @@
 import { redirect } from "next/navigation";
 import RedeemForm from "./RedeemForm";
+import { ContentCard, StatBlock } from "@/components/public/ui";
 import { auth } from "@/lib/auth";
 import { prisma } from "@/lib/prisma";
 
@@ -25,36 +26,29 @@ export default async function RedeemPage() {
   if (!user) redirect("/login");
 
   return (
-    <main>
-      <div className="hero">
-        <h1 style={{ marginBottom: "0.25rem" }}>Redeem a voucher</h1>
-        <p className="muted" style={{ margin: 0 }}>
-          Got a voucher code? Enter it below to add the reward to your account.
-        </p>
-      </div>
+    <main style={{ display: "grid", gap: "1.5rem" }}>
+      <ContentCard
+        icon="🎟️"
+        title="Redeem a voucher"
+        subtitle="Got a voucher code? Enter it below to add the reward to your account."
+      />
 
-      <div className="grid cols-2">
-        <div className="card">
-          <h3 style={{ marginTop: 0 }}>Enter your code</h3>
+      <div className="card-grid sm-2">
+        <ContentCard icon="🔑" title="Enter your code">
           <RedeemForm />
-          <p className="muted" style={{ marginBottom: 0 }}>
+          <p className="muted" style={{ marginBottom: 0, marginTop: "0.85rem" }}>
             Each voucher can only be redeemed once per account.
           </p>
-        </div>
+        </ContentCard>
 
-        <div className="card">
-          <h3 style={{ marginTop: 0 }}>Your balance</h3>
-          <p style={{ margin: "0 0 0.6rem" }}>
-            Signed in as <strong>{user.username}</strong>.
-          </p>
-          <span className="currency">
-            <span className="coin credits">cr</span>
-            {user.credits.toLocaleString()}
-          </span>
+        <ContentCard icon="💰" title="Your balance" subtitle={`Signed in as ${user.username}`}>
+          <div className="stat-grid">
+            <StatBlock value={user.credits.toLocaleString()} label="Credits" icon="🪙" />
+          </div>
           <p className="muted" style={{ marginBottom: 0, marginTop: "0.85rem" }}>
             Redeemed rewards are credited instantly and appear in-game the next time you log in.
           </p>
-        </div>
+        </ContentCard>
       </div>
     </main>
   );