refactor(ui): Rediseño completo de UI con Nuxt UI 4

- Nuevo layout responsivo mobile-first con tabs inferiores
- Sidebar colapsable en desktop con cola de impresión
- Sistema de templates reutilizables con localStorage
- Soporte Dark/Light mode con UColorModeButton
- Composables usePrintQueue y useTemplates para estado global
- Componentes modulares: CommandBuilder, QuickActions, PrintQueue, QueueItem
- Navegación por tabs: Constructor | Cola | Templates

app/components/constructor/QuickActions.vue

@@ -0,0 +1,54 @@
+<script setup lang="ts">
+const queue = usePrintQueue()
+
+const quickActions = [
+  {
+    label: 'Feed 2',
+    icon: 'i-heroicons-arrow-down',
+    ops: [{ op: 'feedLine', line: 2 }]
+  },
+  {
+    label: 'Cortar',
+    icon: 'i-heroicons-scissors',
+    ops: [{ op: 'cut', type: 'feed' }]
+  },
+  {
+    label: 'Pulse',
+    icon: 'i-heroicons-bolt',
+    ops: [{ op: 'pulse', drawer: 'drawer_1', time: 'pulse_200' }]
+  },
+  {
+    label: 'QR',
+    icon: 'i-heroicons-qr-code',
+    ops: [{ op: 'qrcode', data: 'https://example.com', model: 'qrcode_model_2', level: 'level_m', size: 6 }]
+  },
+  {
+    label: 'Barcode',
+    icon: 'i-heroicons-bars-3',
+    ops: [{ op: 'barcode', data: '490123456789', type: 'ean13', hri: 'below', width: 3, height: 80 }]
+  }
+]
+</script>
+
+<template>
+  <UCard variant="soft">
+    <template #header>
+      <span class="text-sm font-medium text-gray-500 dark:text-gray-400">
+        Atajos rápidos
+      </span>
+    </template>
+
+    <div class="flex flex-wrap gap-2">
+      <UButton
+        v-for="action in quickActions"
+        :key="action.label"
+        variant="outline"
+        size="sm"
+        :icon="action.icon"
+        @click="queue.addOperations(action.ops)"
+      >
+        {{ action.label }}
+      </UButton>
+    </div>
+  </UCard>
+</template>