feat(config): agrega personalización de ticket con logo y opciones

- Nuevos endpoints /pos/api/config/receipt (GET/PUT)
- Sección en config.html para subir logo, datos del negocio y toggles visuales
- pos.js carga la config y renderiza el ticket usando logo, RFC, dirección,
  teléfono, mensajes y opciones de desglose/empleado/pago configurables
- Logo se redimensiona a 300px de ancho y se guarda como base64 JPEG en tenant_config

Tests: 35 passed

pos/static/js/pos.js

@@ -30,6 +30,7 @@ const POS = (() => {
     let canEditPrice = false;
     let canCreateWorkshopOrder = false;
     let canCreateLayaway = false;
+    let receiptConfig = {};
 
     // Currency-aware formatter: reads pos_currency from localStorage
     const _posCurrency = localStorage.getItem('pos_currency') || 'MXN';
@@ -134,8 +135,9 @@ const POS = (() => {
             showToast(`Modo conversion: Cotizacion #${convertQuoteId}. El pago convertira la cotizacion en venta.`);
         }
 
-        // Load current register
+        // Load current register and receipt config
         await loadRegister();
+        await loadReceiptConfig();
 
         // Setup event listeners
         setupKeyboard();
@@ -163,6 +165,20 @@ const POS = (() => {
         }
     }
 
+    async function loadReceiptConfig() {
+        try {
+            receiptConfig = await api('/pos/api/config/receipt');
+        } catch (e) {
+            console.warn('Could not load receipt config:', e);
+            receiptConfig = {};
+        }
+    }
+
+    function rc(key, fallback) {
+        const v = receiptConfig[key];
+        return v !== undefined && v !== null && v !== '' ? v : fallback;
+    }
+
     function showOpenRegisterModal() {
         document.getElementById('openRegisterModal').classList.add('open');
         document.getElementById('registerOpenResult').innerHTML = '';
@@ -1283,12 +1299,37 @@ const POS = (() => {
                 </div>`;
         });
 
+        const cfg = receiptConfig || {};
+        const showLogo = cfg.show_logo && cfg.logo;
+        const showRfc = cfg.show_rfc !== false;
+        const showAddress = cfg.show_address;
+        const showPhone = cfg.show_phone;
+        const showIva = cfg.show_iva_breakdown !== false;
+        const showPayment = cfg.show_payment_details !== false;
+        const showEmployee = cfg.show_employee;
+        const storeName = rc('store_name', 'NEXUS AUTOPARTS');
+        const storeTagline = rc('tagline', 'Tu conexion con las refacciones');
+        const storeRfc = rc('rfc', 'NAU210315XX1');
+        const storeAddress = rc('address', '');
+        const storePhone = rc('phone', '');
+        const thanksMsg = rc('thanks_message', 'Gracias por su compra!');
+        const footerMsg = rc('footer', 'Conserve su ticket como comprobante.');
+
+        let storeInfoLines = [];
+        if (currentRegister && currentRegister.branch_name) storeInfoLines.push(`Sucursal: ${currentRegister.branch_name}`);
+        if (showEmployee && sale.employee_name) storeInfoLines.push(`Atendió: ${sale.employee_name}`);
+        if (showRfc && storeRfc) storeInfoLines.push(`RFC: ${storeRfc}`);
+        if (showAddress && storeAddress) storeInfoLines.push(storeAddress);
+        if (showPhone && storePhone) storeInfoLines.push(`Tel: ${storePhone}`);
+
+        const logoHtml = showLogo ? `<div class="ticket-logo-wrap"><img src="${cfg.logo}" alt="Logo" class="ticket-logo" style="max-width:140px;max-height:70px;object-fit:contain;"></div>` : '';
+
         const ticketHtml = `
-            <div class="store-name">NEXUS AUTOPARTS</div>
-            <div class="store-tagline">Tu conexion con las refacciones</div>
+            ${logoHtml}
+            <div class="store-name">${storeName}</div>
+            ${storeTagline ? `<div class="store-tagline">${storeTagline}</div>` : ''}
             <div class="store-info">
-                Sucursal: ${currentRegister ? currentRegister.branch_name || '' : ''}<br>
-                RFC: NAU210315XX1
+                ${storeInfoLines.join('<br>')}
             </div>
             <hr class="divider-double">
             <div class="folio-line">
@@ -1314,13 +1355,12 @@ const POS = (() => {
                     <span>Subtotal:</span><span>${fmt(sale.subtotal)}</span>
                 </div>
                 ${sale.discount_total > 0 ? `<div class="total-line"><span>Descuento:</span><span>-${fmt(sale.discount_total)}</span></div>` : ''}
-                <div class="total-line">
-                    <span>IVA 16%:</span><span>${fmt(sale.tax_total)}</span>
-                </div>
+                ${showIva ? `<div class="total-line"><span>IVA:</span><span>${fmt(sale.tax_total)}</span></div>` : ''}
                 <div class="total-line grand">
                     <span>TOTAL:</span><span>${fmt(sale.total)}</span>
                 </div>
             </div>
+            ${showPayment ? `
             <hr class="divider">
             <div class="payment-section">
                 <div class="ticket-row">
@@ -1333,11 +1373,11 @@ const POS = (() => {
                 <div class="ticket-row" style="font-weight: bold;">
                     <span>Cambio:</span><span>${fmt(sale.change_given || 0)}</span>
                 </div>` : ''}
-            </div>
+            </div>` : ''}
             <hr class="divider">
             <div class="footer-section">
-                <div class="thanks">Gracias por su compra!</div>
-                <div>Conserve su ticket como comprobante.</div>
+                <div class="thanks">${thanksMsg}</div>
+                ${footerMsg ? `<div>${footerMsg}</div>` : ''}
             </div>
         `;