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/components/auth/ActionButtons.vue

@@ -1,6 +1,19 @@
 <template>
   <UCard class="w-full">
     <div class="flex flex-wrap gap-3">
+      <!-- Botón de estado de sesión -->
+      <UButton
+        color="info"
+        size="lg"
+        variant="soft"
+        @click="checkSessionStatus"
+      >
+        <template #leading>
+          <UIcon name="i-heroicons-information-circle" />
+        </template>
+        Estado de Sesión
+      </UButton>
+
       <!-- Botón de perfil -->
       <UButton
         color="primary"
@@ -30,5 +43,5 @@
 </template>
 
 <script setup lang="ts">
-const { logout, goToProfile } = useAuthentik()
+const { logout, goToProfile, checkSessionStatus } = useAuthentik()
 </script>