fix setup form

src/utils/storage.ts

@@ -28,14 +28,14 @@ export function isDuplicateDevice(
 }
 
 
-export function getMerchant(): string {
+export function getMerchant(): MerchantForm | null {
   try {
     return JSON.parse(localStorage.getItem(MERCHANT_KEY) || "");
   } catch {
-    return '';
+    return null;
   }
 }
 
-export function saveMerchant(val: string) {
+export function saveMerchant(val: MerchantForm) {
   localStorage.setItem(MERCHANT_KEY, JSON.stringify(val));
 }