feat: update invoice suffix code generation logic to ensure unique suffix for new invoices

backend/src/classes/Invoice.ts

@@ -111,6 +111,9 @@ class Invoice {
 				}
 			})
 
+			// 更新收据后缀
+			this.suffixCode = maxSuffix ? maxSuffix.invoice_suffix_code + 1 : 1
+
 			// 在数据库中创建新收据
 			const newInvoice = await prisma.invoice.create({
 				data: {