feat: Add comprehensive documentation for Router Lists UI, including setup instructions, API endpoints, and frontend/backend structure; enhance navbar styles for better responsiveness

frontend/src/App.css

@@ -167,12 +167,13 @@
   .navbar-nav .dropdown-menu {
     position: static;
     float: none;
-    width: auto;
-    margin-top: 0;
-    background-color: transparent;
-    border: 0;
-    box-shadow: none;
+    width: 100%;
+    margin-top: 0.25rem;
+    background-color: var(--tblr-bg-surface);
+    border: 1px solid var(--tblr-border-color);
+    box-shadow: 0 0.25rem 0.5rem rgba(0,0,0,0.08);
   }
+  .navbar-nav .dropdown-item { padding: 0.5rem 0.75rem; }
 }
 
 /* Custom animations */

frontend/src/App.jsx

@@ -75,6 +75,7 @@ import {
   useLocation,
   Navigate
 } from 'react-router-dom';
+import { IconMenu2 } from '@tabler/icons-react';
 
 function App() {
   return (
@@ -208,6 +209,19 @@ function MainLayout() {
               <span className="fw-bold">S3 Lists Manager</span>
             </Link>
           </div>
+
+          {/* Кнопка бургера для мобильных */}
+          <button
+            className="navbar-toggler d-md-none"
+            type="button"
+            data-bs-toggle="collapse"
+            data-bs-target="#navbar-menu"
+            aria-controls="navbar-menu"
+            aria-expanded="false"
+            aria-label="Toggle navigation"
+          >
+            <IconMenu2 />
+          </button>
           
           {/* Основное меню */}
           <div className="collapse navbar-collapse" id="navbar-menu">
@@ -264,7 +278,7 @@ function MainLayout() {
           </div>
           
           {/* Правая часть навбара: язык и тема */}
-          <div className="navbar-nav flex-row order-md-last">
+          <div className="navbar-nav flex-row order-md-last ms-2">
             <div className="nav-item me-2">
               <select
                 className="form-select form-select-sm"

frontend/src/components/PageHeaderActions.jsx

@@ -26,7 +26,7 @@ function PageHeaderActions({
   onBackgroundUpdate,
 }) {
   return (
-    <div className="header-actions">
+    <div className="header-actions" role="toolbar" aria-label="Действия страницы">
       <div className="btn-group">
         {onOnlineUpdate && (
           <button className="btn btn-outline-warning" type="button" onClick={onOnlineUpdate} title="Online-обновление BGP (WebSocket)">