feat: add notifications view and update branding

- Add complete notifications management view with:
  - Service status display (Discord, Telegram)
  - Test notification functionality
  - Service management (delete/disable)
  - Filter settings display (case sensitive/insensitive)
- Update API types to match current backend structure
- Fix NotificationFilters type (remove deprecated fields)
- Update page title from 'Vite + React + TS' to 'Leggen'
- Replace Vite favicon with custom Leggen favicon
- Add notifications tab to main navigation
- Ensure full API compatibility with current backend

frontend/src/lib/api.ts

@@ -1,5 +1,5 @@
 import axios from 'axios';
-import type { Account, Transaction, Balance, ApiResponse } from '../types/api';
+import type { Account, Transaction, Balance, ApiResponse, NotificationSettings, NotificationTest, NotificationService, NotificationServicesResponse } from '../types/api';
 
 const API_BASE_URL = import.meta.env.VITE_API_URL || 'http://localhost:8000/api/v1';
 
@@ -62,6 +62,36 @@ export const apiClient = {
     const response = await api.get<ApiResponse<Transaction>>(`/transactions/${id}`);
     return response.data.data;
   },
+
+  // Get notification settings
+  getNotificationSettings: async (): Promise<NotificationSettings> => {
+    const response = await api.get<ApiResponse<NotificationSettings>>('/notifications/settings');
+    return response.data.data;
+  },
+
+  // Update notification settings
+  updateNotificationSettings: async (settings: NotificationSettings): Promise<NotificationSettings> => {
+    const response = await api.put<ApiResponse<NotificationSettings>>('/notifications/settings', settings);
+    return response.data.data;
+  },
+
+  // Test notification
+  testNotification: async (test: NotificationTest): Promise<void> => {
+    await api.post('/notifications/test', test);
+  },
+
+  // Get notification services
+  getNotificationServices: async (): Promise<NotificationService[]> => {
+    const response = await api.get<ApiResponse<NotificationServicesResponse>>('/notifications/services');
+    // Convert object to array format
+    const servicesData = response.data.data;
+    return Object.values(servicesData);
+  },
+
+  // Delete notification service
+  deleteNotificationService: async (service: string): Promise<void> => {
+    await api.delete(`/notifications/settings/${service}`);
+  },
 };
 
 export default apiClient;