Added SSE function and add readAt for notification

src/store/useNotificationStore.ts

@@ -0,0 +1,14 @@
+import { create } from 'zustand';
+
+type NotifyState = {
+  hasNew: boolean;
+  setHasNew: (hasNew: boolean) => void;
+};
+
+const useNotificationStore = create<NotifyState>((set) => ({
+  hasNew: false,
+  setHasNew: (hasNew: boolean) => set({ hasNew }),
+  toggleNew: () => set((state) => ({ hasNew: !state.hasNew })),
+}));
+
+export default useNotificationStore;