feat: Variables programáticas en templates

Permite definir variables en templates con sintaxis {{nombre🏷️default}}
- Auto-detección de variables al guardar templates
- Drawer para completar valores al cargar template con variables
- Badge mostrando cantidad de variables en tarjeta de template
- Resolución de variables antes de cargar en cola

server/utils/templates.ts

@@ -4,9 +4,14 @@ import { existsSync } from 'fs'
 import { join } from 'path'
 
 export interface Operation {
-  id: string
-  type: 'text' | 'feed' | 'cut' | 'pulse' | 'image' | 'barcode' | 'qrcode'
-  params: Record<string, unknown>
+  op: string
+  [key: string]: any
+}
+
+export interface TemplateVariable {
+  name: string
+  label?: string
+  defaultValue?: string
 }
 
 export interface PrintTemplate {
@@ -14,10 +19,42 @@ export interface PrintTemplate {
   name: string
   description?: string
   operations: Operation[]
+  variables: TemplateVariable[]
   createdAt: string
   updatedAt: string
 }
 
+// Regex para detectar {{nombre}}, {{nombre:label}}, {{nombre:label:default}}
+const VARIABLE_REGEX = /\{\{(\w+)(?::([^:}]+))?(?::([^}]+))?\}\}/g
+
+// Extraer variables de las operaciones
+export function extractVariables(operations: Operation[]): TemplateVariable[] {
+  const variablesMap = new Map<string, TemplateVariable>()
+
+  for (const op of operations) {
+    // Buscar en campos que pueden contener variables
+    const searchFields = ['value', 'data']
+    for (const field of searchFields) {
+      if (typeof op[field] === 'string') {
+        const matches = op[field].matchAll(VARIABLE_REGEX)
+        for (const match of matches) {
+          const [, name, label, defaultValue] = match
+          // Solo guardar la primera definición de cada variable
+          if (!variablesMap.has(name)) {
+            variablesMap.set(name, {
+              name,
+              label: label || undefined,
+              defaultValue: defaultValue || undefined
+            })
+          }
+        }
+      }
+    }
+  }
+
+  return Array.from(variablesMap.values())
+}
+
 export interface TemplatesStore {
   templates: PrintTemplate[]
 }
@@ -84,6 +121,7 @@ export async function createTemplate(data: {
     name: data.name,
     description: data.description || '',
     operations: data.operations,
+    variables: extractVariables(data.operations),
     createdAt: now,
     updatedAt: now
   }
@@ -103,9 +141,15 @@ export async function updateTemplate(id: string, data: Partial<{
 
   if (index === -1) return null
 
+  // Si se actualizan las operaciones, recalcular las variables
+  const variables = data.operations
+    ? extractVariables(data.operations)
+    : store.templates[index].variables
+
   store.templates[index] = {
     ...store.templates[index],
     ...data,
+    variables,
     updatedAt: new Date().toISOString()
   }