refactor: update builderNm field in session management

- Set builderNm in session and response payload based on user data for improved session tracking.
- Ensured consistency in session management structures.

src/app/api/auth/route.ts

@@ -57,7 +57,7 @@ export async function POST(request: Request) {
     session.storeLvl = result.data.data.storeLvl
     session.custCd = result.data.data.custCd
     session.builderNo = result.data.data.builderNo
-    session.builderNm = ''
+    session.builderNm = result.data.data.builderNm
     session.isLoggedIn = true
 
     if (result.data.data.userId === 'T01') {
@@ -105,7 +105,7 @@ export async function POST(request: Request) {
       STORE_LVL: result.data.data.storeLvl,
       CUST_CD: result.data.data.custCd,
       BUILDER_NO: result.data.data.builderNo,
-      BUILDER_NM: '',
+      BUILDER_NM: result.data.data.builderNm,
       IS_LOGGED_IN: true,
       ROLE: '',
     }