修正 OALAUNCH1 登录与业务流回归（05-28-oalaunch1-parallel-closeout）

client/src/pages/LoginPage.tsx

@@ -76,7 +76,7 @@ export function LoginPage() {
     queryFn: () => fetchAuthCapabilities(),
     staleTime: 60_000,
   });
-  const emailDeliveryReady = authCapabilitiesQuery.data?.emailDelivery.ready === true;
+  const emailDeliveryReady = authCapabilitiesQuery.data?.emailDelivery?.ready === true;
   const emailDeliveryChecking = authCapabilitiesQuery.isLoading;
   const emailDeliveryUnavailable = authCapabilitiesQuery.isSuccess && !emailDeliveryReady;
   const emailDeliveryUnknown = authCapabilitiesQuery.isError;