Implement rate limiting and enhance authentication flow

- Added rate limiting configuration for authentication endpoints, allowing customizable request limits via environment variables.
- Updated authentication flow to utilize HttpRequest for cookie management, ensuring secure handling of refresh tokens.
- Introduced a new endpoint to retrieve user subscription details.
- Enhanced the handling of Telegram bot token validation to prevent errors with empty tokens.
- Updated the application to serialize enums as strings for better documentation and compatibility with TypeScript.
- Improved test coverage for new features and adjustments in command handlers.

frontend/src/routes/admin.tsx

@@ -0,0 +1,43 @@
+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 })
+
+const TABS = [
+  { to: '/admin', key: 'overview' },
+  { to: '/admin/activation', key: 'activation' },
+  { to: '/admin/users', key: 'users' },
+  { to: '/admin/roles', key: 'roles' },
+  { to: '/admin/nodes', key: 'nodes' },
+  { to: '/admin/apps', key: 'apps' },
+  { to: '/admin/audit', key: 'audit' },
+] as const
+
+function AdminLayout() {
+  const { t } = useTranslation()
+  const { isReady } = useRequireAdmin()
+
+  if (!isReady) return null
+
+  return (
+    <div className="mx-auto flex w-full max-w-5xl flex-col gap-6 px-6 py-10">
+      <h1 className="text-2xl font-semibold tracking-tight">{t('nav.admin')}</h1>
+      <nav className="flex gap-1 border-b border-border">
+        {TABS.map((tab) => (
+          <Link
+            key={tab.to}
+            to={tab.to}
+            activeOptions={{ exact: tab.to === '/admin' }}
+            className={cn('px-3 py-2 text-sm text-muted-foreground hover:text-foreground')}
+            activeProps={{ className: 'border-b-2 border-primary text-foreground font-medium' }}
+          >
+            {t(`admin.tabs.${tab.key}`)}
+          </Link>
+        ))}
+      </nav>
+      <Outlet />
+    </div>
+  )
+}