feat: adicionar página de Monitorização

- React Router para SPA routing
- Página /monitor com status de sistemas
- Cards de servidores, serviços, sites, containers
- Barras de progresso animadas
- Auto-refresh de 60s
- Link no header do dashboard

DeskCRM Task: #1604

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/main.tsx

@@ -1,10 +1,17 @@
 import { StrictMode } from 'react'
 import { createRoot } from 'react-dom/client'
+import { BrowserRouter, Routes, Route } from 'react-router-dom'
 import './index.css'
 import App from './App.tsx'
+import Monitor from './pages/Monitor.tsx'
 
 createRoot(document.getElementById('root')!).render(
   <StrictMode>
-    <App />
+    <BrowserRouter>
+      <Routes>
+        <Route path="/" element={<App />} />
+        <Route path="/monitor" element={<Monitor />} />
+      </Routes>
+    </BrowserRouter>
   </StrictMode>,
 )