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]/(authenticated)/layout.tsx

@@ -0,0 +1,28 @@
+/**
+ * Authenticated Route Group Layout
+ * Wraps all authenticated routes with AuthGuard and provides common layout structure
+ */
+
+import type { Metadata } from 'next';
+import { AuthGuard } from '@/components/auth';
+import { Header } from '@/components/layout/Header';
+import { Footer } from '@/components/layout/Footer';
+
+export const metadata: Metadata = {
+  title: {
+    template: '%s | FastNext Template',
+    default: 'Dashboard',
+  },
+};
+
+export default function AuthenticatedLayout({ children }: { children: React.ReactNode }) {
+  return (
+    <AuthGuard>
+      <div className="flex min-h-screen flex-col">
+        <Header />
+        <main className="flex-1">{children}</main>
+        <Footer />
+      </div>
+    </AuthGuard>
+  );
+}

frontend/src/app/[locale]/(authenticated)/settings/layout.tsx

@@ -0,0 +1,78 @@
+/**
+ * Settings Layout
+ * Provides tabbed navigation for settings pages
+ */
+
+'use client';
+
+import { usePathname } from '@/lib/i18n/routing';
+import { Link } from '@/lib/i18n/routing';
+import { Tabs, TabsList, TabsTrigger } from '@/components/ui/tabs';
+import { User, Lock, Monitor, Settings as SettingsIcon } from 'lucide-react';
+
+/**
+ * Settings tabs configuration
+ */
+const settingsTabs = [
+  {
+    value: 'profile',
+    label: 'Profile',
+    href: '/settings/profile',
+    icon: User,
+  },
+  {
+    value: 'password',
+    label: 'Password',
+    href: '/settings/password',
+    icon: Lock,
+  },
+  {
+    value: 'sessions',
+    label: 'Sessions',
+    href: '/settings/sessions',
+    icon: Monitor,
+  },
+  {
+    value: 'preferences',
+    label: 'Preferences',
+    href: '/settings/preferences',
+    icon: SettingsIcon,
+  },
+];
+
+export default function SettingsLayout({ children }: { children: React.ReactNode }) {
+  const pathname = usePathname();
+
+  // Determine active tab based on pathname
+  const activeTab = settingsTabs.find((tab) => pathname.startsWith(tab.href))?.value || 'profile';
+
+  return (
+    <div className="container mx-auto px-4 py-8">
+      {/* Page Header */}
+      <div className="mb-8">
+        <h1 className="text-3xl font-bold text-foreground">Settings</h1>
+        <p className="mt-2 text-muted-foreground">Manage your account settings and preferences</p>
+      </div>
+
+      {/* Tabs Navigation */}
+      <Tabs value={activeTab} className="space-y-6">
+        <TabsList className="grid w-full grid-cols-2 md:grid-cols-4 lg:w-[600px]">
+          {settingsTabs.map((tab) => {
+            const Icon = tab.icon;
+            return (
+              <TabsTrigger key={tab.value} value={tab.value} asChild>
+                <Link href={tab.href} className="flex items-center space-x-2">
+                  <Icon className="h-4 w-4" />
+                  <span>{tab.label}</span>
+                </Link>
+              </TabsTrigger>
+            );
+          })}
+        </TabsList>
+
+        {/* Tab Content */}
+        <div className="rounded-lg border bg-card text-card-foreground p-6">{children}</div>
+      </Tabs>
+    </div>
+  );
+}

frontend/src/app/[locale]/(authenticated)/settings/page.tsx

@@ -0,0 +1,11 @@
+/**
+ * Settings Index Page
+ * Redirects to /settings/profile
+ */
+
+import { redirect } from 'next/navigation';
+
+export default async function SettingsPage({ params }: { params: Promise<{ locale: string }> }) {
+  const { locale } = await params;
+  redirect(`/${locale}/settings/profile`);
+}

frontend/src/app/[locale]/(authenticated)/settings/password/page.tsx

@@ -0,0 +1,23 @@
+/**
+ * Password Settings Page
+ * Secure password change functionality for authenticated users
+ */
+
+'use client';
+
+import { PasswordChangeForm } from '@/components/settings';
+
+export default function PasswordSettingsPage() {
+  return (
+    <div className="space-y-6">
+      <div>
+        <h2 className="text-2xl font-semibold text-foreground">Password Settings</h2>
+        <p className="text-muted-foreground mt-1">
+          Change your password to keep your account secure
+        </p>
+      </div>
+
+      <PasswordChangeForm />
+    </div>
+  );
+}

frontend/src/app/[locale]/(authenticated)/settings/preferences/page.tsx

@@ -0,0 +1,21 @@
+/**
+ * User Preferences Page
+ * Theme, notifications, and other preferences
+ */
+
+/* istanbul ignore next - Next.js type import for metadata */
+import type { Metadata } from 'next';
+
+/* istanbul ignore next - Next.js metadata, not executable code */
+export const metadata: Metadata = {
+  title: 'Preferences',
+};
+
+export default function PreferencesPage() {
+  return (
+    <div>
+      <h2 className="text-2xl font-semibold text-foreground mb-4">Preferences</h2>
+      <p className="text-muted-foreground">Configure your preferences (Coming in Task 3.5)</p>
+    </div>
+  );
+}

frontend/src/app/[locale]/(authenticated)/settings/profile/page.tsx

@@ -0,0 +1,21 @@
+/**
+ * Profile Settings Page
+ * User profile management - edit name, email, and other profile information
+ */
+
+'use client';
+
+import { ProfileSettingsForm } from '@/components/settings';
+
+export default function ProfileSettingsPage() {
+  return (
+    <div className="space-y-6">
+      <div>
+        <h2 className="text-2xl font-semibold text-foreground">Profile Settings</h2>
+        <p className="text-muted-foreground mt-1">Manage your profile information</p>
+      </div>
+
+      <ProfileSettingsForm />
+    </div>
+  );
+}

frontend/src/app/[locale]/(authenticated)/settings/sessions/page.tsx

@@ -0,0 +1,23 @@
+/**
+ * Session Management Page
+ * View and manage active sessions across all devices
+ */
+
+'use client';
+
+import { SessionsManager } from '@/components/settings';
+
+export default function SessionsPage() {
+  return (
+    <div className="space-y-6">
+      <div>
+        <h2 className="text-2xl font-semibold text-foreground">Active Sessions</h2>
+        <p className="text-muted-foreground mt-1">
+          View and manage devices signed in to your account
+        </p>
+      </div>
+
+      <SessionsManager />
+    </div>
+  );
+}