feat: add AppLayout, BrandLogo, ProfileMenu, and RouteBadge components

- Implemented AppLayout component for application shell with navigation and sidebar.
- Created BrandLogo component to display the application logo.
- Developed ProfileMenu component for user profile management with dropdown functionality.
- Added RouteBadge component to visually represent route numbers with color coding.

style: add CSS styles for Dashboard and Routes pages

- Introduced Dashboard.css for styling the dashboard layout and components.
- Created RoutesPage.css for styling the routes page, including filters and table layout.
- Added SchedulesPage.css for styling the schedules layout and route options.

backend/test/alertNotificationService.test.js

@@ -18,7 +18,7 @@ function createLogger() {
   };
 }
 
-test('sends an exact alert-created notification and string-only data payload', async () => {
+test('sends an exact data-only alert-created message with string-only data', async () => {
   const messages = [];
   const service = new AlertNotificationService({
     enabled: true,
@@ -52,10 +52,6 @@ test('sends an exact alert-created notification and string-only data payload', a
   assert.equal(messages.length, 1);
   assert.deepEqual(messages[0], {
     topic: 'route_alerts',
-    notification: {
-      title: 'Автобус задерживается',
-      body: 'Задержка около 15 минут'
-    },
     data: {
       event: 'alert_created',
       alertId: '42',
@@ -63,16 +59,19 @@ test('sends an exact alert-created notification and string-only data payload', a
       routeId: '7',
       routeNumber: '12',
       startTime: '2026-07-11T08:30:00.000Z',
-      endTime: '2026-07-11T09:30:00.000Z'
+      endTime: '2026-07-11T09:30:00.000Z',
+      title: 'Автобус задерживается',
+      body: 'Задержка около 15 минут'
     },
     android: {
-      priority: 'high',
-      notification: {
-        channelId: 'route_alerts',
-        tag: 'alert_42'
-      }
+      priority: 'high'
     }
   });
+  assert.equal('notification' in messages[0], false);
+  assert.equal('notification' in messages[0].android, false);
+  assert.equal(messages[0].android.priority, 'high');
+  assert.equal(messages[0].data.title, 'Автобус задерживается');
+  assert.equal(messages[0].data.body, 'Задержка около 15 минут');
   assert.ok(Object.values(messages[0].data).every((value) => typeof value === 'string'));
 });
 
@@ -92,6 +91,10 @@ test('serializes a null route id and missing optional values as empty strings',
   assert.equal(message.data.routeNumber, '');
   assert.equal(message.data.startTime, '');
   assert.equal(message.data.endTime, '');
+  assert.equal(message.data.title, 'Новость');
+  assert.equal(message.data.body, 'Важная информация');
+  assert.equal('notification' in message, false);
+  assert.equal('notification' in message.android, false);
 });
 
 test('does not initialize messaging or send for an inactive alert', async () => {
@@ -207,8 +210,8 @@ test('uses the requested Russian title fallbacks and a route-aware body fallback
       route_number: '5'
     });
 
-    assert.equal(message.notification.title, expectedTitle);
-    assert.equal(message.notification.body, 'Актуальная информация по маршруту №5');
+    assert.equal(message.data.title, expectedTitle);
+    assert.equal(message.data.body, 'Актуальная информация по маршруту №5');
   }
 
   const withoutRoute = buildAlertCreatedMessage({
@@ -217,7 +220,7 @@ test('uses the requested Russian title fallbacks and a route-aware body fallback
     title: '',
     message: ''
   });
-  assert.equal(withoutRoute.notification.body, 'Актуальная информация о движении транспорта');
+  assert.equal(withoutRoute.data.body, 'Актуальная информация о движении транспорта');
 });
 
 test('reads disabled-by-default Firebase configuration and environment overrides', () => {