fix: resolve blank screen on return from external links

frontend/src/views/DiscoverView.vue

@@ -12,7 +12,7 @@ import AuthGuard from '@/components/common/AuthGuard.vue'
 const router = useRouter()
 const { t } = useI18n()
 const businesses  = ref<Business[]>([])
-const isLoading   = ref(true)
+const isLoading   = ref(false)
 const error       = ref<string | null>(null)
 const searchQuery = ref('')
 const selectedCategory = ref('Todas')
@@ -41,21 +41,28 @@ function catIcon(cat: string) {
   return CATEGORY_META[cat]?.icon ?? 'place'
 }
 
-async function loadBusinesses() {
-  isLoading.value = true
+async function loadBusinesses(silent = false) {
+  // Modo 'silencioso': si ya tenemos datos, no mostrar spinner — solo refrescar en fondo
+  if (!silent || businesses.value.length === 0) {
+    isLoading.value = true
+  }
   error.value = null
   try {
     businesses.value = await businessService.getAllBusinesses()
   } catch (e) {
     console.error('Error loading businesses:', e)
-    error.value = t('discover.error')
+    // Solo mostrar error si no hay datos previos
+    if (businesses.value.length === 0) {
+      error.value = t('discover.error')
+    }
   } finally {
     isLoading.value = false
   }
 }
 
 function handleRefocus() {
-  loadBusinesses()
+  // Recarga silenciosa: no congela la UI si ya hay datos visibles
+  loadBusinesses(true)
 }
 
 onMounted(() => {
@@ -179,7 +186,7 @@ function resetFilters() {
     <div v-else-if="error" class="state-center">
       <span class="material-icons" style="font-size: 3.5rem; color: #ef4444; opacity: 0.8; margin-bottom: 0.5rem;">error_outline</span>
       <p style="font-weight: 600; color: var(--text-secondary);">{{ error }}</p>
-      <button class="cta-btn" style="margin-top: 1rem;" @click="loadBusinesses">
+      <button class="cta-btn" style="margin-top: 1rem;" @click="loadBusinesses()">
         <span class="material-icons">refresh</span>
         {{ t('common.retry') }}
       </button>