Fix expired calculation to be 6 months from now instead of setting to June

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/stores/login.ts

@@ -17,7 +17,7 @@ export default defineStore('loginStore', {
     userData: {},
     isLoggedIn: false,
     rememberedReturnToUrl: "",
-    expired: new Date().setMonth(6), // 設定 Refresh Token 的到期日為半年後
+    expired: (() => { const d = new Date(); d.setMonth(d.getMonth() + 6); return d.getTime(); })(), // 設定 Refresh Token 的到期日為半年後
   }),
   actions: {
     /**