feat: Sistema de gestión de impresoras persistente

- Crear modelo Printer con campos: id, name, host, deviceId, timeout, isDefault
- Almacenamiento persistente en data/printers.json
- APIs CRUD: GET/POST /api/printers, GET/PUT/DELETE /api/printers/:id
- API para seleccionar impresora activa: POST /api/printers/select
- Endpoint de impresión ahora usa la impresora seleccionada o la especificada por printerId
- Composable usePrinters() para el cliente
- UI: Selector de impresora en sidebar, tab Impresoras en mobile
- Componentes: PrintersList, PrintersCard, PrintersForm, PrintersSelector

app/components/printers/Card.vue

@@ -0,0 +1,89 @@
+<script setup lang="ts">
+import type { Printer } from '~/composables/usePrinters'
+
+const props = defineProps<{
+  printer: Printer
+  isSelected: boolean
+}>()
+
+const emit = defineEmits<{
+  select: []
+  edit: []
+  delete: []
+  setDefault: []
+}>()
+
+const menuItems = computed(() => [
+  [
+    {
+      label: 'Editar',
+      icon: 'i-heroicons-pencil-square',
+      click: () => emit('edit')
+    },
+    {
+      label: props.printer.isDefault ? 'Es predeterminada' : 'Hacer predeterminada',
+      icon: 'i-heroicons-star',
+      disabled: props.printer.isDefault,
+      click: () => emit('setDefault')
+    }
+  ],
+  [
+    {
+      label: 'Eliminar',
+      icon: 'i-heroicons-trash',
+      color: 'error' as const,
+      click: () => emit('delete')
+    }
+  ]
+])
+</script>
+
+<template>
+  <UCard
+    :class="[
+      'cursor-pointer transition-all',
+      isSelected ? 'ring-2 ring-primary-500' : 'hover:bg-gray-50 dark:hover:bg-gray-800'
+    ]"
+    @click="emit('select')"
+  >
+    <div class="flex items-start justify-between">
+      <div class="flex-1">
+        <div class="flex items-center gap-2">
+          <h3 class="font-semibold text-gray-900 dark:text-white">
+            {{ printer.name }}
+          </h3>
+          <UBadge v-if="printer.isDefault" color="primary" variant="subtle" size="xs">
+            Default
+          </UBadge>
+          <UBadge v-if="isSelected" color="success" variant="subtle" size="xs">
+            Seleccionada
+          </UBadge>
+        </div>
+
+        <div class="mt-2 space-y-1 text-sm text-gray-500 dark:text-gray-400">
+          <div class="flex items-center gap-2">
+            <UIcon name="i-heroicons-globe-alt" class="w-4 h-4" />
+            <span>{{ printer.host }}</span>
+          </div>
+          <div class="flex items-center gap-2">
+            <UIcon name="i-heroicons-identification" class="w-4 h-4" />
+            <span>{{ printer.deviceId }}</span>
+          </div>
+          <div class="flex items-center gap-2">
+            <UIcon name="i-heroicons-clock" class="w-4 h-4" />
+            <span>{{ printer.timeout }}ms timeout</span>
+          </div>
+        </div>
+      </div>
+
+      <UDropdownMenu :items="menuItems" @click.stop>
+        <UButton
+          icon="i-heroicons-ellipsis-vertical"
+          color="neutral"
+          variant="ghost"
+          size="sm"
+        />
+      </UDropdownMenu>
+    </div>
+  </UCard>
+</template>