add authentication with login form and token management

frontend/src/types/index.ts

@@ -28,3 +28,18 @@ export const statusLabels: Record<DeliveryStatus, string> = {
   new: 'Новое',
   delivered: 'Доставлено',
 };
+
+// Auth types
+export interface LoginRequest {
+  username: string;
+  password: string;
+}
+
+export interface LoginResponse {
+  token: string;
+}
+
+export interface User {
+  id: string;
+  username: string;
+}