feat: Enhance error handling with showErrorToast utility

- Replaced existing toast error messages with the new `showErrorToast` utility across multiple components, improving consistency in error reporting.
- Updated error messages to provide more specific guidance for users, enhancing the overall user experience during error scenarios.
- Ensured that all relevant error handling in batch management, external call configurations, cascading management, and screen management components now utilizes the new utility for better maintainability.

frontend/components/pop/management/PopScreenSettingModal.tsx

@@ -33,6 +33,7 @@ import {
   Save,
 } from "lucide-react";
 import { toast } from "sonner";
+import { showErrorToast } from "@/lib/utils/toastUtils";
 import { ScreenDefinition } from "@/types/screen";
 import { screenApi } from "@/lib/api/screen";
 import { PopScreenGroup, getPopScreenGroups } from "@/lib/api/popScreenGroup";
@@ -191,7 +192,7 @@ export function PopScreenSettingModal({
       onOpenChange(false);
     } catch (error) {
       console.error("저장 실패:", error);
-      toast.error("저장에 실패했습니다.");
+      showErrorToast("POP 화면 설정 저장에 실패했습니다", error, { guidance: "입력 데이터를 확인하고 다시 시도해 주세요." });
     } finally {
       setSaving(false);
     }