Refactor chat interface and enhance user experience

- Updated the ChatWindow component to provide clearer instructions and actions when no conversation is selected, improving user guidance.
- Redesigned the MenuBar to display session timeout information more effectively.
- Enhanced the SearchView component with a more user-friendly country selection using a Multiselect dropdown.
- Improved the UserList component to display user age and gender, enhancing user profile visibility.
- Updated various views (ChatView, FaqView, FeedbackView, PartnersView, RulesView, SafetyView) to include a consistent app branding link for better navigation.

These changes collectively enhance the chat interface, improve user engagement, and streamline navigation across the application.

client/src/views/RulesView.vue

@@ -1,13 +1,13 @@
 <template>
   <div class="chat-container">
     <header class="header">
-      <div class="app-brand">
+      <router-link to="/" class="app-brand app-brand-link">
         <span class="app-brand-mark">S</span>
         <div class="app-brand-copy">
           <span class="app-brand-eyebrow">SingleChat</span>
           <h1>Regeln</h1>
         </div>
-      </div>
+      </router-link>
       <HeaderAdBanner />
     </header>
 
@@ -80,5 +80,9 @@ import ImprintContainer from '../components/ImprintContainer.vue';
   margin: 18px 0 6px;
   color: #18201b;
 }
+
+.app-brand-link {
+  text-decoration: none;
+}
 </style>