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/List.vue

@@ -0,0 +1,132 @@
+<script setup lang="ts">
+const printers = usePrinters()
+const toast = useToast()
+
+const showDrawer = ref(false)
+const editingPrinter = ref<typeof printers.printers.value[0] | null>(null)
+
+// Cargar impresoras al montar
+onMounted(() => {
+  printers.fetchPrinters()
+})
+
+function openNewPrinter() {
+  editingPrinter.value = null
+  showDrawer.value = true
+}
+
+function openEditPrinter(printer: typeof printers.printers.value[0]) {
+  editingPrinter.value = printer
+  showDrawer.value = true
+}
+
+async function handleSubmit(data: {
+  name: string
+  host: string
+  deviceId: string
+  timeout: number
+  isDefault: boolean
+}) {
+  if (editingPrinter.value) {
+    const result = await printers.updatePrinter(editingPrinter.value.id, data)
+    if (result) {
+      toast.add({ title: 'Impresora actualizada', color: 'success' })
+      showDrawer.value = false
+    } else {
+      toast.add({ title: printers.error.value || 'Error', color: 'error' })
+    }
+  } else {
+    const result = await printers.createPrinter(data)
+    if (result) {
+      toast.add({ title: 'Impresora agregada', color: 'success' })
+      showDrawer.value = false
+    } else {
+      toast.add({ title: printers.error.value || 'Error', color: 'error' })
+    }
+  }
+}
+
+async function handleSelect(printer: typeof printers.printers.value[0]) {
+  await printers.selectPrinter(printer.id)
+}
+
+async function handleSetDefault(printer: typeof printers.printers.value[0]) {
+  const result = await printers.updatePrinter(printer.id, { isDefault: true })
+  if (result) {
+    toast.add({ title: 'Impresora predeterminada actualizada', color: 'success' })
+  }
+}
+
+async function handleDelete(printer: typeof printers.printers.value[0]) {
+  if (!confirm(`¿Eliminar la impresora "${printer.name}"?`)) return
+
+  const result = await printers.deletePrinter(printer.id)
+  if (result) {
+    toast.add({ title: 'Impresora eliminada', color: 'success' })
+  } else {
+    toast.add({ title: printers.error.value || 'Error', color: 'error' })
+  }
+}
+</script>
+
+<template>
+  <div class="space-y-4">
+    <div class="flex items-center justify-between">
+      <h2 class="text-lg font-semibold text-gray-900 dark:text-white">
+        Impresoras
+      </h2>
+      <UButton
+        icon="i-heroicons-plus"
+        @click="openNewPrinter"
+      >
+        Agregar
+      </UButton>
+    </div>
+
+    <div v-if="printers.loading.value" class="flex justify-center py-8">
+      <UIcon name="i-heroicons-arrow-path" class="w-8 h-8 animate-spin text-gray-400" />
+    </div>
+
+    <div v-else-if="printers.printers.value.length === 0" class="text-center py-8">
+      <UIcon name="i-heroicons-printer" class="w-12 h-12 text-gray-400 mx-auto mb-2" />
+      <p class="text-gray-500 dark:text-gray-400">
+        No hay impresoras configuradas
+      </p>
+      <p class="text-sm text-gray-400 dark:text-gray-500 mb-4">
+        Agrega una impresora para comenzar a imprimir
+      </p>
+      <UButton @click="openNewPrinter">
+        Agregar primera impresora
+      </UButton>
+    </div>
+
+    <div v-else class="grid gap-3 sm:grid-cols-2">
+      <PrintersCard
+        v-for="printer in printers.printers.value"
+        :key="printer.id"
+        :printer="printer"
+        :is-selected="printer.id === printers.selectedPrinterId.value"
+        @select="handleSelect(printer)"
+        @edit="openEditPrinter(printer)"
+        @delete="handleDelete(printer)"
+        @set-default="handleSetDefault(printer)"
+      />
+    </div>
+
+    <UDrawer v-model:open="showDrawer">
+      <template #header>
+        <h3 class="text-lg font-semibold">
+          {{ editingPrinter ? 'Editar impresora' : 'Nueva impresora' }}
+        </h3>
+      </template>
+
+      <div class="p-4">
+        <PrintersForm
+          :printer="editingPrinter"
+          @submit="handleSubmit"
+          @cancel="showDrawer = false"
+        />
+      </div>
+    </UDrawer>
+  </div>
+</template>