fix(core): update

ts/interfaces.ts

@@ -0,0 +1,33 @@
+export interface IXInvoice {
+  InvoiceNumber: string;
+  DateIssued: string; // Date in ISO 8601 format
+  Seller: IParty;
+  Buyer: IParty;
+  Items: IInvoiceItem[];
+  TotalAmount: number;
+}
+
+export interface IParty {
+  Name: string;
+  Address: IAddress;
+  Contact: IContact;
+}
+
+export interface IAddress {
+  Street: string;
+  City: string;
+  PostalCode: string;
+  Country: string;
+}
+
+export interface IContact {
+  Email: string;
+  Phone: string;
+}
+
+export interface IInvoiceItem {
+  Description: string;
+  Quantity: number;
+  UnitPrice: number;
+  TotalPrice: number;
+}