feat: Cerrar menú al tocar fuera y efecto fade en overlay

frontend/src/components/AppHeader.vue

@@ -15,6 +15,11 @@
       
       <ReportModal :is-open="showReportModal" @close="showReportModal = false" />
       
+      <!-- Overlay para cerrar el menú al tocar fuera -->
+      <Transition name="fade">
+        <div v-if="showMenu" class="menu-overlay" @click="showMenu = false"></div>
+      </Transition>
+
       <Transition name="menu-slide">
         <div v-if="showMenu" class="menu-dropdown sibu-sidebar">
           <div class="sibu-header-plain">
@@ -417,6 +422,16 @@ const handleLogout = () => {
     z-index: 9999;
 }
 
+.fade-enter-active,
+.fade-leave-active {
+  transition: opacity 0.3s ease;
+}
+
+.fade-enter-from,
+.fade-leave-to {
+  opacity: 0;
+}
+
 .menu-slide-enter-active,
 .menu-slide-leave-active {
   transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);