add campaign observability page

src/components/Layout.tsx

@@ -1,6 +1,6 @@
 import { useState, useEffect } from 'react';
 import { Outlet, Link, useLocation } from 'react-router-dom';
-import { LayoutDashboard, Users, BarChart3, ChevronLeft, ChevronRight, Package, Loader2, LogOut } from 'lucide-react';
+import { LayoutDashboard, Users, BarChart3, ChevronLeft, ChevronRight, Package, Loader2, LogOut, Megaphone } from 'lucide-react';
 import type { DateRange, OrderData, StockData } from '../types';
 import { fetchData, fetchStock, logout } from '../dataService';
 
@@ -77,6 +77,7 @@ const Layout = () => {
     { name: 'Dashboard', href: '/graph', icon: LayoutDashboard },
     { name: 'Produtos', href: '/products', icon: Package },
     { name: 'Clientes', href: '/clients', icon: Users },
+    { name: 'Campanhas', href: '/campaigns', icon: Megaphone },
   ];
 
   return (