feat(web): anticipo total, importe aplicado y saldo pendiente en el pie de facturas y notas de crédito

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

apps/web/src/app/features/documents/document-form.page.ts

@@ -421,6 +421,14 @@ export class DocumentFormPage {
         return this.fmt(this.totals().expenses);
       case 'tax':
         return this.fmt(this.totals().tax);
+      case 'downPayment':
+        return this.fmt(Number(this.doc()?.['DownPaymentAmount'] ?? 0));
+      case 'applied':
+        return this.fmt(Number(this.doc()?.['PaidToDate'] ?? 0));
+      case 'balance': {
+        const d = this.doc();
+        return this.fmt(d ? Number(d['DocTotal'] ?? 0) - Number(d['PaidToDate'] ?? 0) : 0);
+      }
       case 'total':
         return this.fmt(this.totals().total);
     }