feat: integrate Tailwind CSS and implement dark mode functionality

- Added Tailwind CSS dependencies and configured PostCSS.
- Updated app component to wrap router outlet with a styled div for dark mode support.
- Modified routing to include a default route and added auth guards.
- Implemented dark mode toggle functionality in content component.
- Enhanced login component with improved styling and lifecycle management.
- Created items component with basic structure and routing.
- Added global styles for body and dark mode variants.
- Updated tests for new items component.

Web/src/app/app.routes.ts

@@ -1,20 +1,27 @@
 import { Routes } from '@angular/router';
 import { Login } from './login/login';
 import { authGuard } from './app.route.guard';
+import { App } from './app';
 
 export const routes: Routes = [
+    {
+        path: '',
+        component: App
+    },
     {
         path: 'login',
         component: Login,
+        canActivate: [authGuard]
     },
     {
         path: 'content',
+        loadComponent: () => import('./content/content').then(m => m.Content),
+        canActivate: [authGuard],
         children: [
             {
-                path: '',
-                loadComponent: () => import('./content/content').then(m => m.Content),
+                path: 'items',
+                loadComponent: () => import('./content/items/items').then(m => m.Items),
                 canActivate: [authGuard],
-            }
-        ],
+            }]
     }
 ];