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

server/utils/printer.ts

@@ -0,0 +1,62 @@
+// Utilidades para comunicación con impresoras Epson ePOS
+import axios from 'axios'
+import https from 'https'
+
+export interface PrinterResponse {
+  status: number
+  headers: any
+  data: string
+}
+
+export function buildSoapEnvelope(inner: string): string {
+  return (
+    '<?xml version="1.0" encoding="utf-8"?>' +
+    '<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">' +
+    '<s:Body>' +
+    '<epos-print xmlns="http://www.epson-pos.com/schemas/2011/03/epos-print">' +
+    inner +
+    '</epos-print>' +
+    '</s:Body>' +
+    '</s:Envelope>'
+  )
+}
+
+export async function sendToPrinter(
+  xml: string,
+  printerHost: string,
+  printerDeviceId: string,
+  printerTimeoutMs: number
+): Promise<PrinterResponse> {
+  const url = `https://${printerHost}/cgi-bin/epos/service.cgi?devid=${encodeURIComponent(printerDeviceId)}&timeout=${printerTimeoutMs}`
+
+  // Agente HTTPS que acepta certificados auto-firmados
+  const httpsAgent = new https.Agent({
+    rejectUnauthorized: false
+  })
+
+  const res = await axios.post(url, xml, {
+    headers: {
+      'Content-Type': 'text/xml; charset=utf-8'
+    },
+    httpsAgent,
+    timeout: printerTimeoutMs + 5000,
+    validateStatus: () => true, // Aceptar cualquier status code
+  })
+
+  return {
+    status: res.status,
+    headers: res.headers,
+    data: typeof res.data === 'string' ? res.data : String(res.data)
+  }
+}
+
+export function parsePrinterResponse(responseData: string): {
+  success: boolean
+  code: string
+} {
+  const success = /success\s*=\s*"true"/.test(responseData)
+  const codeMatch = responseData.match(/code="([^"]*)"/)
+  const code = codeMatch ? codeMatch[1] : ''
+
+  return { success, code }
+}