fix: send canonical login identifier

src/modules/auth/api/auth.ts

@@ -27,8 +27,8 @@ export interface ImpersonationExchangeResult {
   expiresIn: number
 }
 
-export function loginMerchant(username: string, password: string) {
+export function loginMerchant(loginId: string, password: string) {
-  return apiRequest<TokenPair>({ method: 'POST', url: '/auth/login', data: { username, password } })
+  return apiRequest<TokenPair>({ method: 'POST', url: '/auth/login', data: { loginId, password } })
 }
 
 export function registerMerchant(payload: RegisterMerchantRequest) {