Add session status check button

Add new button to check and display current session status:
- New checkSessionStatus() function in useAuthentik composable
- Displays toast notification with session info
- Shows user name if authenticated or warning if not
- Add UNotifications component to app.vue to render toasts

This allows users to quickly verify their authentication status.

nuxt4/app/composables/useAuthentik.ts

@@ -50,10 +50,33 @@ export const useAuthentik = () => {
     navigateTo(`${authentikUrl}/if/user/`, { external: true, open: { target: '_blank' } })
   }
 
+  const checkSessionStatus = () => {
+    const toast = useToast()
+
+    if (isAuthenticated.value && user.value) {
+      toast.add({
+        title: 'Sesión Activa',
+        description: `Conectado como: ${user.value.name || user.value.username}`,
+        color: 'success',
+        icon: 'i-heroicons-check-circle',
+        timeout: 5000
+      })
+    } else {
+      toast.add({
+        title: 'Sin Sesión',
+        description: 'No hay sesión activa en este momento',
+        color: 'warning',
+        icon: 'i-heroicons-exclamation-triangle',
+        timeout: 5000
+      })
+    }
+  }
+
   return {
     user,
     isAuthenticated,
     logout,
-    goToProfile
+    goToProfile,
+    checkSessionStatus
   }
 }