Port AtomCMS atom theme faithfully (Tailwind v4 + real CSS/assets + shell)

Make the template match the atom theme, not just approximate it:
- Add Tailwind v4 (+forms/typography plugins, postcss) and port the real atom
  CSS (global.css + atom app.css) into globals.css: nav-item underline, currency
  + navigation icon classes, site-bg, card-base/hover-lift, text utils — asset
  paths adapted to /assets.
- Copy the real theme assets (backgrounds, icons/currency/navigation, profile,
  leaderboards) into public/assets.
- Rebuild the shell 1:1 from the atom Blade: TopHeader (currency pills +
  user/admin dropdowns, auth-only), SiteHeader (header image + black/50 overlay,
  logo+online+Nitro client / guest Login+Create-account CTA), Navigation (white
  bar, nav-item + Community/Assistance dropdowns), Footer. ThemeVars injects the
  DB-driven CSS custom properties into :root like app.blade.php. Layout uses the
  atom body/site-bg + grid-cols-12 max-w-7xl content wrapper.

Verified: tsc 0, next build exit 0; curl confirms the atom markup, compiled CSS
references the assets, and background-light.jpg + currency/navigation icons all
serve 200.

src/components/navigation.tsx

@@ -0,0 +1,94 @@
+import Link from "next/link";
+import { auth } from "@/lib/auth";
+
+export async function Navigation() {
+  const session = await auth();
+  const isStaff = (session?.user?.rank ?? 0) >= 7;
+
+  return (
+    <nav className="relative shadow-sm" style={{ backgroundColor: "var(--color-navbar)" }}>
+      <div className="max-w-7xl min-h-[60px] px-4 flex items-center gap-x-6 md:gap-x-8 mx-auto flex-wrap">
+        <Link href="/" className="nav-item">
+          <i className="navigation-icon home mr-1 hidden lg:inline-flex" />
+          Home
+        </Link>
+
+        <details className="relative">
+          <summary className="nav-item list-none cursor-pointer [&::-webkit-details-marker]:hidden">
+            <i className="navigation-icon community mr-1 hidden lg:inline-flex" />
+            Community
+          </summary>
+          <div
+            className="absolute left-0 mt-1 min-w-[190px] rounded-md shadow-lg z-50 py-1"
+            style={{ backgroundColor: "var(--color-dropdown)" }}
+          >
+            <Link href="/news" className="dropdown-item">
+              Articles
+            </Link>
+            <Link href="/photos" className="dropdown-item">
+              Photos
+            </Link>
+            <Link href="/staff" className="dropdown-item">
+              Staff
+            </Link>
+            <Link href="/rankings" className="dropdown-item">
+              Rankings
+            </Link>
+            <Link href="/guilds" className="dropdown-item">
+              Guilds
+            </Link>
+          </div>
+        </details>
+
+        <Link href="/leaderboard" className="nav-item">
+          <i className="navigation-icon leaderboards mr-1 hidden lg:inline-flex" />
+          Leaderboards
+        </Link>
+        <Link href="/rares" className="nav-item">
+          Rare values
+        </Link>
+        <Link href="/shop" className="nav-item">
+          <i className="navigation-icon shop mr-1 hidden lg:inline-flex" />
+          Shop
+        </Link>
+        <Link href="/marketplace" className="nav-item">
+          Market
+        </Link>
+
+        <details className="relative">
+          <summary className="nav-item list-none cursor-pointer [&::-webkit-details-marker]:hidden">
+            <i className="navigation-icon rules mr-1 hidden lg:inline-flex" />
+            Assistance
+          </summary>
+          <div
+            className="absolute left-0 mt-1 min-w-[190px] rounded-md shadow-lg z-50 py-1"
+            style={{ backgroundColor: "var(--color-dropdown)" }}
+          >
+            <Link href="/help" className="dropdown-item">
+              Help center
+            </Link>
+            {session?.user ? (
+              <Link href="/help/tickets" className="dropdown-item">
+                My tickets
+              </Link>
+            ) : null}
+            <Link href="/badges" className="dropdown-item">
+              Badges
+            </Link>
+          </div>
+        </details>
+
+        {session?.user ? (
+          <Link href="/friends" className="nav-item">
+            Friends
+          </Link>
+        ) : null}
+        {isStaff ? (
+          <Link href="/admin" className="nav-item">
+            Admin
+          </Link>
+        ) : null}
+      </div>
+    </nav>
+  );
+}