Remove all obsolete authentication, settings, admin, and demo-related components and pages

- Eliminated redundant components, pages, and layouts related to authentication (`login`, `register`, `password-reset`, etc.), user settings, admin, and demos.
- Simplified the frontend structure by removing unused dynamic imports, forms, and test code.
- Refactored configurations and metadata imports to exclude references to removed features.
- Streamlined the project for future development and improved maintainability by discarding legacy and unused code.

frontend/src/app/[locale]/admin/page.tsx

@@ -0,0 +1,92 @@
+/**
+ * Admin Dashboard Page
+ * Displays admin statistics and management options
+ * Protected by AuthGuard in layout with requireAdmin=true
+ */
+
+/* istanbul ignore next - Next.js type import for metadata */
+import type { Metadata } from 'next';
+import { Link } from '@/lib/i18n/routing';
+import { DashboardStats } from '@/components/admin';
+import {
+  UserGrowthChart,
+  OrganizationDistributionChart,
+  SessionActivityChart,
+  UserStatusChart,
+} from '@/components/charts';
+import { Users, Building2, Settings } from 'lucide-react';
+
+/* istanbul ignore next - Next.js metadata, not executable code */
+export const metadata: Metadata = {
+  title: 'Admin Dashboard',
+};
+
+export default function AdminPage() {
+  return (
+    <div className="container mx-auto px-6 py-8">
+      <div className="space-y-8">
+        {/* Page Header */}
+        <div>
+          <h1 className="text-3xl font-bold tracking-tight">Admin Dashboard</h1>
+          <p className="mt-2 text-muted-foreground">
+            Manage users, organizations, and system settings
+          </p>
+        </div>
+
+        {/* Stats Grid */}
+        <DashboardStats />
+
+        {/* Quick Actions */}
+        <div>
+          <h2 className="text-xl font-semibold mb-4">Quick Actions</h2>
+          <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
+            <Link href="/admin/users" className="block">
+              <div className="rounded-lg border bg-card p-6 transition-colors hover:bg-accent cursor-pointer">
+                <div className="flex items-center gap-3 mb-2">
+                  <Users className="h-5 w-5 text-primary" aria-hidden="true" />
+                  <h3 className="font-semibold">User Management</h3>
+                </div>
+                <p className="text-sm text-muted-foreground">
+                  View, create, and manage user accounts
+                </p>
+              </div>
+            </Link>
+
+            <Link href="/admin/organizations" className="block">
+              <div className="rounded-lg border bg-card p-6 transition-colors hover:bg-accent cursor-pointer">
+                <div className="flex items-center gap-3 mb-2">
+                  <Building2 className="h-5 w-5 text-primary" aria-hidden="true" />
+                  <h3 className="font-semibold">Organizations</h3>
+                </div>
+                <p className="text-sm text-muted-foreground">
+                  Manage organizations and their members
+                </p>
+              </div>
+            </Link>
+
+            <Link href="/admin/settings" className="block">
+              <div className="rounded-lg border bg-card p-6 transition-colors hover:bg-accent cursor-pointer">
+                <div className="flex items-center gap-3 mb-2">
+                  <Settings className="h-5 w-5 text-primary" aria-hidden="true" />
+                  <h3 className="font-semibold">System Settings</h3>
+                </div>
+                <p className="text-sm text-muted-foreground">Configure system-wide settings</p>
+              </div>
+            </Link>
+          </div>
+        </div>
+
+        {/* Analytics Charts */}
+        <div>
+          <h2 className="text-xl font-semibold mb-4">Analytics Overview</h2>
+          <div className="grid gap-6 md:grid-cols-2">
+            <UserGrowthChart />
+            <SessionActivityChart />
+            <OrganizationDistributionChart />
+            <UserStatusChart />
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+}