Initial commit: base slice (auth, roles, users, admin) scaffold

Backend: .NET 10 Clean Architecture + LiteCqrs.Net + EF Core/PostgreSQL +
Identity/JWT. Frontend: React 19 + Vite + TanStack Query/Router + Tailwind v4
with a retro CRT theme. Docker/compose deployment mirroring PnvPanel's
conventions, scoped down to the current base feature set.

frontend/src/routes/admin.tsx

@@ -0,0 +1,36 @@
+import { createFileRoute, Link, Outlet } from '@tanstack/react-router'
+import { useTranslation } from 'react-i18next'
+import { useRequireAdmin } from '@/features/auth/guards'
+import { cn } from '@/shared/lib/cn'
+
+export const Route = createFileRoute('/admin')({ component: AdminLayout })
+
+function AdminLayout() {
+  const { t } = useTranslation()
+  const { isReady } = useRequireAdmin()
+
+  if (!isReady) return null
+
+  return (
+    <div className="flex flex-col gap-6">
+      <h1 className="crt-glow text-2xl font-bold">{t('nav.admin')}</h1>
+      <nav className="flex gap-4 border-b border-border text-sm">
+        <Link
+          to="/admin/roles"
+          className={cn('pb-2 uppercase tracking-wide text-muted-foreground hover:text-foreground')}
+          activeProps={{ className: 'border-b-2 border-primary text-primary' }}
+        >
+          {t('admin.roles.title')}
+        </Link>
+        <Link
+          to="/admin/users"
+          className={cn('pb-2 uppercase tracking-wide text-muted-foreground hover:text-foreground')}
+          activeProps={{ className: 'border-b-2 border-primary text-primary' }}
+        >
+          {t('admin.users.title')}
+        </Link>
+      </nav>
+      <Outlet />
+    </div>
+  )
+}