fix(frontend/admin): Fix admin routing - remove duplicate AdminLayout wrappers

PROBLEM:
- /admin redirects to / (home page)
- Admin pages were wrapping themselves in <AdminLayout>
- This caused double-nested layout (header, nav, footer twice)

ROOT CAUSE:
Admin pages (AdminDashboardPage, AdminUsersPage, etc.) were individually wrapping
their content in <AdminLayout> component. But the App.tsx routing already renders
<AdminLayout> as the parent element for all /admin routes, and AdminLayout uses
<Outlet /> to render child routes.

This created a nested structure:
AppLayout -> AdminLayout (from routing) -> AdminLayout (from page) -> Page Content

SOLUTION:
- Removed <AdminLayout> wrappers from all admin pages
- AdminLayout now always uses <Outlet /> instead of {children || <Outlet />}
- Removed unused 'children' parameter from AdminLayout
- Admin pages now render directly in the Outlet of AdminLayout

CHANGES:
- AdminDashboardPage.tsx: Removed AdminLayout import and all <AdminLayout> tags
- AdminUsersPage.tsx: Removed AdminLayout import and all <AdminLayout> tags
- AdminUserDetailPage.tsx: Removed AdminLayout import and all <AdminLayout> tags
- AdminReportsPage.tsx: Removed AdminLayout import and all <AdminLayout> tags
- AdminStoryGeneratorPage.tsx: Removed AdminLayout import and all <AdminLayout> tags
- AdminLayout.tsx: Removed unused children parameter, always use <Outlet />

Now /admin will correctly render the AdminLayout with nested admin pages.

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

german-app-frontend/src/components/features/admin/AdminLayout.tsx

@@ -5,9 +5,8 @@
 
 import { NavLink, Outlet, useNavigate } from 'react-router-dom';
 import { useAuth } from '@/stores/authStore';
-import type { ReactNode } from 'react';
 
-export function AdminLayout({ children }: { children?: ReactNode }) {
+export function AdminLayout() {
   const { user, logout } = useAuth();
   const navigate = useNavigate();
 
@@ -53,7 +52,7 @@ export function AdminLayout({ children }: { children?: ReactNode }) {
       </header>
 
       <main className="admin-main">
-        {children || <Outlet />}
+        <Outlet />
       </main>
 
       <footer className="admin-footer">

german-app-frontend/src/pages/AdminDashboardPage.tsx

@@ -7,7 +7,6 @@ import { useEffect, useState } from 'react';
 import { useAuth } from '@/stores/authStore';
 import { getDashboardStats } from '@/lib/api/admin';
 import type { DashboardStats } from '@/types/api/admin';
-import { AdminLayout } from '@/components/features/admin/AdminLayout';
 
 export function AdminDashboardPage() {
   const { token } = useAuth();
@@ -36,25 +35,20 @@ export function AdminDashboardPage() {
 
   if (loading) {
     return (
-      <AdminLayout>
       <div className="loading-overlay">
         <div className="spinner"></div>
         <p>Loading dashboard...</p>
       </div>
-      </AdminLayout>
     );
   }
 
   if (error) {
     return (
-      <AdminLayout>
       <div className="error-message">{error}</div>
-      </AdminLayout>
     );
   }
 
   return (
-    <AdminLayout>
     <div className="admin-dashboard">
         <header className="dashboard-header">
           <h1>Dashboard</h1>
@@ -152,6 +146,5 @@ export function AdminDashboardPage() {
           </p>
         </section>
       </div>
-    </AdminLayout>
   );
 }

german-app-frontend/src/pages/AdminReportsPage.tsx

@@ -7,7 +7,6 @@ import { useEffect, useState, useCallback } from 'react';
 import { useAuth } from '@/stores/authStore';
 import { getAllUserReports, getFullUserReport, exportReportsAsCsv } from '@/lib/api/admin';
 import type { UserProgressReport, FullUserReport } from '@/types/api/admin';
-import { AdminLayout } from '@/components/features/admin/AdminLayout';
 
 export function AdminReportsPage() {
   const { token } = useAuth();
@@ -92,17 +91,17 @@ export function AdminReportsPage() {
 
   if (loading) {
     return (
-      <AdminLayout>
+      
         <div className="loading-overlay">
           <div className="spinner"></div>
           <p>Loading reports...</p>
         </div>
-      </AdminLayout>
+      
     );
   }
 
   return (
-    <AdminLayout>
+    
       <div className="admin-reports">
         <header className="reports-header">
           <h1>User Progress Reports</h1>
@@ -338,6 +337,6 @@ export function AdminReportsPage() {
           )}
         </div>
       </div>
-    </AdminLayout>
+    
   );
 }

german-app-frontend/src/pages/AdminStoryGeneratorPage.tsx

@@ -5,7 +5,6 @@
 
 import { useEffect, useState, useCallback } from 'react';
 import { useAuth } from '@/stores/authStore';
-import { AdminLayout } from '@/components/features/admin/AdminLayout';
 import {
   getLevelsWithStories,
   generateStory,
@@ -159,17 +158,17 @@ export function AdminStoryGeneratorPage() {
 
   if (loading && levels.length === 0) {
     return (
-      <AdminLayout>
+      
         <div className="loading-overlay">
           <div className="spinner"></div>
           <p>Loading levels...</p>
         </div>
-      </AdminLayout>
+      
     );
   }
 
   return (
-    <AdminLayout>
+    
       <div className="admin-story-generator">
         <header className="story-generator-header">
           <h1>Story Generator</h1>
@@ -385,6 +384,6 @@ export function AdminStoryGeneratorPage() {
           </ul>
         </section>
       </div>
-    </AdminLayout>
+    
   );
 }

german-app-frontend/src/pages/AdminUserDetailPage.tsx

@@ -6,7 +6,6 @@
 import { useEffect, useState, useCallback } from 'react';
 import { useParams, useNavigate } from 'react-router-dom';
 import { useAuth } from '@/stores/authStore';
-import { AdminLayout } from '@/components/features/admin/AdminLayout';
 import { getUserById, getFullUserReport } from '@/lib/api/admin';
 import type { AdminUserDetails, FullUserReport } from '@/types/api/admin';
 
@@ -76,26 +75,26 @@ export function AdminUserDetailPage() {
 
   if (loading) {
     return (
-      <AdminLayout>
+      
         <div className="loading-overlay">
           <div className="spinner"></div>
           <p>Loading user details...</p>
         </div>
-      </AdminLayout>
+      
     );
   }
 
   if (error) {
     return (
-      <AdminLayout>
+      
         <div className="error-message admin-error">{error}</div>
-      </AdminLayout>
+      
     );
   }
 
   if (!user) {
     return (
-      <AdminLayout>
+      
         <div className="no-data">
           <h2>User Not Found</h2>
           <p>The user you're looking for doesn't exist or has been deleted.</p>
@@ -103,12 +102,12 @@ export function AdminUserDetailPage() {
             Back to Users
           </button>
         </div>
-      </AdminLayout>
+      
     );
   }
 
   return (
-    <AdminLayout>
+    
       <div className="admin-user-detail">
         {/* Header */}
         <header className="user-detail-header">
@@ -328,6 +327,6 @@ export function AdminUserDetailPage() {
           </div>
         </section>
       </div>
-    </AdminLayout>
+    
   );
 }

german-app-frontend/src/pages/AdminUsersPage.tsx

@@ -7,7 +7,6 @@ import { useEffect, useState, useCallback } from 'react';
 import { useAuth } from '@/stores/authStore';
 import { getAllUsers, updateUserRole, deleteUser } from '@/lib/api/admin';
 import type { AdminUserListItem } from '@/types/api/admin';
-import { AdminLayout } from '@/components/features/admin/AdminLayout';
 
 export function AdminUsersPage() {
   const { token } = useAuth();
@@ -78,17 +77,17 @@ export function AdminUsersPage() {
 
   if (loading) {
     return (
-      <AdminLayout>
+      
         <div className="loading-overlay">
           <div className="spinner"></div>
           <p>Loading users...</p>
         </div>
-      </AdminLayout>
+      
     );
   }
 
   return (
-    <AdminLayout>
+    
       <div className="admin-users">
         <header className="users-header">
           <h1>User Management</h1>
@@ -205,6 +204,6 @@ export function AdminUsersPage() {
           </div>
         )}
       </div>
-    </AdminLayout>
+    
   );
 }