feat(customers): habilitar edición de clientes desde la lista

- Hace clickeables las filas de la tabla para seleccionar un cliente y
  mostrar su panel de detalle (donde ya existe el botón Editar).
- Agrega botón de acción rápida con icono de lápiz en cada fila para
  abrir directamente el modal de edición.
- Extrae openEditModal y agrega editCustomer(id) para cargar el cliente
  vía API y abrir el modal sin depender de la selección previa.
- Actualiza colspan del estado vacío de 9 a 11 por la nueva columna.

pos/static/js/customers.js

@@ -107,7 +107,7 @@ const Customers = (() => {
         const num = String(c.id).padStart(5, '0');
         const selClass = (currentCustomer && currentCustomer.id === c.id) ? 'selected' : '';
         const isChecked = selectedCustomers.has(c.id) ? 'checked' : '';
-        return '<tr class="' + selClass + '">' +
+        return '<tr class="' + selClass + '" onclick="Customers.selectCustomer(' + c.id + ')">' +
             '<td onclick="event.stopPropagation();"><input type="checkbox" ' + isChecked + ' onchange="Customers.toggleCustomerSelection(' + c.id + ')"></td>' +
             '<td class="cell-num">' + num + '</td>' +
             '<td>' +
@@ -121,6 +121,7 @@ const Customers = (() => {
             '<td class="cell-credit ' + creditClass + '">' + fmt(available) + '</td>' +
             '<td class="cell-date hide-mobile">' + formatDate(c.last_purchase || c.created_at) + '</td>' +
             '<td>' + statusBadge(c) + '</td>' +
+            '<td onclick="event.stopPropagation();"><button class="btn btn-sm btn-ghost" title="Editar cliente" onclick="Customers.editCustomer(' + c.id + ')"><svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M11 4H4a2 2 0 0 0-2 2v14a2 2 0 0 0 2 2h14a2 2 0 0 0 2-2v-7"/><path d="M18.5 2.5a2.121 2.121 0 0 1 3 3L12 15l-4 1 1-4 9.5-9.5z"/></svg></button></td>' +
             '</tr>';
     }
 
@@ -131,7 +132,7 @@ const Customers = (() => {
         if (!tbody) return;
 
         if (!customers || customers.length === 0) {
-            tbody.innerHTML = '<tr><td colspan="9">' + renderEmptyState({
+            tbody.innerHTML = '<tr><td colspan="11">' + renderEmptyState({
                 icon: '<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"><path d="M17 21v-2a4 4 0 0 0-4-4H5a4 4 0 0 0-4 4v2"/><circle cx="9" cy="7" r="4"/><path d="M23 21v-2a4 4 0 0 0-3-3.87M16 3.13a4 4 0 0 1 0 7.75"/></svg>',
                 title: 'Sin clientes',
                 subtitle: 'No se encontraron clientes registrados.',
@@ -146,7 +147,7 @@ const Customers = (() => {
                 rowHeight: 52,
                 buffer: 3,
                 renderRow: renderCustomerRow,
-                emptyHtml: '<tr><td colspan="9">' + renderEmptyState({ title: 'Sin clientes', subtitle: 'No hay clientes registrados.' }) + '</td></tr>'
+                emptyHtml: '<tr><td colspan="11">' + renderEmptyState({ title: 'Sin clientes', subtitle: 'No hay clientes registrados.' }) + '</td></tr>'
             });
         }
         customersVS.setData(customers);
@@ -415,9 +416,22 @@ const Customers = (() => {
 
     function editCurrent() {
         if (!currentCustomer) return;
-        const c = currentCustomer;
+        openEditModal(currentCustomer);
+    }
+
+    async function editCustomer(id) {
+        try {
+            const c = await api(`/pos/api/customers/${id}`);
+            currentCustomer = c;
+            openEditModal(c);
+        } catch (e) {
+            alert('Error: ' + e.message);
+        }
+    }
+
+    function openEditModal(c) {
         const modal = document.getElementById('customerModal');
-        if (!modal) return;
+        if (!modal || !c) return;
         document.getElementById('modalTitle').textContent = 'Editar Cliente';
         document.getElementById('editId').value = c.id;
         const safeSet = (id, v) => { const el = document.getElementById(id); if (el) el.value = v; };
@@ -802,7 +816,7 @@ const Customers = (() => {
     const publicApi = {
         search, goToPage, loadCustomers,
         showDetail, selectCustomer, closeDetail,
-        showCreateModal, editCurrent, closeModal, save,
+        showCreateModal, editCurrent, editCustomer, closeModal, save,
         showStatement, closeStatement,
         showPaymentModal, closePayment, recordPayment,
     };