goldenChat base source add

frontend/src/utils/appEntry.ts

@@ -0,0 +1,14 @@
+/** 앱 진입(스플래시 통과) — 탭 세션 단위 */
+const ENTERED_KEY = 'gc_app_entered';
+
+export function isAppEntered(): boolean {
+  return sessionStorage.getItem(ENTERED_KEY) === '1';
+}
+
+export function setAppEntered(): void {
+  sessionStorage.setItem(ENTERED_KEY, '1');
+}
+
+export function clearAppEntered(): void {
+  sessionStorage.removeItem(ENTERED_KEY);
+}