fix(pdf): change document page format to Media Carta Vertical (5.5x8.5 inches)

lib/features/referrals/services/department_referral_pdf_service.dart

@@ -6,8 +6,8 @@ import 'package:pdf/widgets.dart' as pw;
 import 'package:printing/printing.dart';
 
 class DepartmentReferralPdfService {
-  /// Genera el documento PDF de Referimiento a Departamento en formato Media Carta Horizontal
-  /// (8.5 x 5.5 pulgadas / 612 x 396 pt), idéntico a AlfaMedical.
+  /// Genera el documento PDF de Referimiento a Departamento en formato Media Carta Vertical
+  /// (5.5 x 8.5 pulgadas / 396 x 612 pt).
   static Future<Uint8List> buildDepartmentReferralPdf({
     required String doctorName,
     required String specialty,
@@ -23,16 +23,15 @@ class DepartmentReferralPdfService {
     final pdf = pw.Document(title: 'Referir a Departamento');
     final formattedDate = DateFormat('dd/MM/yyyy').format(date ?? DateTime.now());
 
-    // Formato exacto e idéntico a AlfaMedical (ReportLab):
-    // pagesize = (8.5*inch, 5.5*inch)
-    // leftMargin = 72, rightMargin = 72, topMargin = 18, bottomMargin = 18.
+    // Formato Media Carta Vertical (5.5 x 8.5 pulgadas / 396 x 612 pt):
+    // Margen equilibrado de media pulgada (36 pt) a los lados y 20 pt vertical
     const pageFormat = PdfPageFormat(
-      8.5 * PdfPageFormat.inch,
       5.5 * PdfPageFormat.inch,
-      marginLeft: 72,
-      marginRight: 72,
-      marginTop: 18,
-      marginBottom: 18,
+      8.5 * PdfPageFormat.inch,
+      marginLeft: 36,
+      marginRight: 36,
+      marginTop: 20,
+      marginBottom: 20,
     );
 
     // Tipografías estándar con fallback a fuentes base PDF si no hay conexión a internet