diff --git a/src/components/items/ItemMasterDataManagement/tabs/MasterFieldTab/index.tsx b/src/components/items/ItemMasterDataManagement/tabs/MasterFieldTab/index.tsx
index cad851c1..add97845 100644
--- a/src/components/items/ItemMasterDataManagement/tabs/MasterFieldTab/index.tsx
+++ b/src/components/items/ItemMasterDataManagement/tabs/MasterFieldTab/index.tsx
@@ -1,3 +1,5 @@
+'use client';
+
 /**
  * 항목 탭 컴포넌트
  *
diff --git a/src/components/material/ReceivingManagement/ImportInspectionInputModal.tsx b/src/components/material/ReceivingManagement/ImportInspectionInputModal.tsx
index 470b893d..3faf92d5 100644
--- a/src/components/material/ReceivingManagement/ImportInspectionInputModal.tsx
+++ b/src/components/material/ReceivingManagement/ImportInspectionInputModal.tsx
@@ -837,7 +837,7 @@ export function ImportInspectionInputModal({
         <DialogHeader className="px-6 pt-6 pb-0 shrink-0">
           <div className="flex items-center gap-2">
             <DialogTitle className="text-lg font-bold">수입검사</DialogTitle>
-            {template && (
+            {process.env.NODE_ENV === 'development' && template && (
               <button
                 type="button"
                 onClick={isTestFilled ? clearTestData : fillTestData}
diff --git a/src/components/organisms/StatCards.tsx b/src/components/organisms/StatCards.tsx
index 36dab11b..2e8f7c58 100644
--- a/src/components/organisms/StatCards.tsx
+++ b/src/components/organisms/StatCards.tsx
@@ -44,7 +44,7 @@ export function StatCards({ stats }: StatCardsProps) {
             } ${
               stat.isActive ? 'border-primary bg-primary/5' : ''
             } ${
-              count % 2 === 1 && index === count - 1 ? 'col-span-2 sm:col-span-1' : ''
+              count % 2 === 1 && index === count - 1 && count < 6 ? 'col-span-2 sm:col-span-1' : ''
             }`}
             onClick={stat.onClick}
           >
diff --git a/src/components/settings/NotificationSettings/actions.ts b/src/components/settings/NotificationSettings/actions.ts
index 879f636f..fbd5126c 100644
--- a/src/components/settings/NotificationSettings/actions.ts
+++ b/src/components/settings/NotificationSettings/actions.ts
@@ -2,17 +2,16 @@
 
 
 import { executeServerAction, type ActionResult } from '@/lib/api/execute-server-action';
+import { buildApiUrl } from '@/lib/api/query-params';
 import type { NotificationSettings } from './types';
 import { DEFAULT_NOTIFICATION_SETTINGS } from './types';
 
-const API_URL = process.env.NEXT_PUBLIC_API_URL;
-
 // ===== 알림 설정 조회 =====
 export async function getNotificationSettings(): Promise<{
   success: boolean; data: NotificationSettings; error?: string; __authError?: boolean;
 }> {
   const result = await executeServerAction({
-    url: `${API_URL}/api/v1/settings/notifications`,
+    url: buildApiUrl('/api/v1/settings/notifications'),
     transform: (data: Record<string, unknown>) => transformApiToFrontend(data),
     errorMessage: '알림 설정 조회에 실패했습니다.',
   });
@@ -30,7 +29,7 @@ export async function getNotificationSettings(): Promise<{
 // ===== 알림 설정 저장 =====
 export async function saveNotificationSettings(settings: NotificationSettings): Promise<ActionResult> {
   return executeServerAction({
-    url: `${API_URL}/api/v1/settings/notifications`,
+    url: buildApiUrl('/api/v1/settings/notifications'),
     method: 'PUT',
     body: transformFrontendToApi(settings),
     errorMessage: '알림 설정 저장에 실패했습니다.',
diff --git a/src/components/settings/NotificationSettings/index.tsx b/src/components/settings/NotificationSettings/index.tsx
index 3df6464d..05ebb781 100644
--- a/src/components/settings/NotificationSettings/index.tsx
+++ b/src/components/settings/NotificationSettings/index.tsx
@@ -7,7 +7,7 @@
  * 항목 설정 기능으로 표시할 알림 카테고리/항목을 선택할 수 있습니다.
  */
 
-import { useState, useCallback } from 'react';
+import { useState, useCallback, useRef } from 'react';
 import { PageLayout } from '@/components/organisms/PageLayout';
 import { PageHeader } from '@/components/organisms/PageHeader';
 import { Bell, Save, Play, Settings } from 'lucide-react';
@@ -28,38 +28,16 @@ import { SOUND_OPTIONS, DEFAULT_ITEM_VISIBILITY } from './types';
 import { saveNotificationSettings } from './actions';
 import { ItemSettingsDialog } from './ItemSettingsDialog';
 
-// 미리듣기 - Audio API 재생
-let previewAudio: HTMLAudioElement | null = null;
-
-function playPreviewSound(soundType: SoundType) {
-  if (soundType === 'mute') {
-    toast.info('무음으로 설정되어 있습니다.');
-    return;
-  }
-
-  // 이전 재생 중지
-  if (previewAudio) {
-    previewAudio.pause();
-    previewAudio = null;
-  }
-
-  const soundFile = soundType === 'sam_voice' ? 'sam_voice.wav' : 'default.wav';
-  previewAudio = new Audio(`/sounds/${soundFile}`);
-  previewAudio.play().catch(() => {
-    const soundName = soundType === 'default' ? '기본 알림음' : 'SAM 보이스';
-    toast.info(`${soundName} 미리듣기 (음원 파일 준비 중)`);
-  });
-}
-
 // 알림 항목 컴포넌트
 interface NotificationItemRowProps {
   label: string;
   item: NotificationItem;
   onChange: (item: NotificationItem) => void;
+  onPlayPreview: (soundType: SoundType) => void;
   disabled?: boolean;
 }
 
-function NotificationItemRow({ label, item, onChange, disabled }: NotificationItemRowProps) {
+function NotificationItemRow({ label, item, onChange, onPlayPreview, disabled }: NotificationItemRowProps) {
   const isDisabled = disabled || !item.enabled;
 
   return (
@@ -107,7 +85,7 @@ function NotificationItemRow({ label, item, onChange, disabled }: NotificationIt
               variant="outline"
               size="icon"
               className="h-8 w-8 shrink-0"
-              onClick={() => playPreviewSound(item.soundType)}
+              onClick={() => onPlayPreview(item.soundType)}
               disabled={isDisabled}
             >
               <Play className="h-3 w-3" />
@@ -190,6 +168,28 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
     toast.success('항목 설정이 저장되었습니다.');
   }, []);
 
+  // 미리듣기 - Audio API 재생 (useRef로 메모리 누수 방지)
+  const previewAudioRef = useRef<HTMLAudioElement | null>(null);
+
+  const handlePlayPreview = useCallback((soundType: SoundType) => {
+    if (soundType === 'mute') {
+      toast.info('무음으로 설정되어 있습니다.');
+      return;
+    }
+
+    if (previewAudioRef.current) {
+      previewAudioRef.current.pause();
+      previewAudioRef.current = null;
+    }
+
+    const soundFile = soundType === 'sam_voice' ? 'sam_voice.wav' : 'default.wav';
+    previewAudioRef.current = new Audio(`/sounds/${soundFile}`);
+    previewAudioRef.current.play().catch(() => {
+      const soundName = soundType === 'default' ? '기본 알림음' : 'SAM 보이스';
+      toast.info(`${soundName} 미리듣기 (음원 파일 준비 중)`);
+    });
+  }, []);
+
   // 공지 알림 핸들러
   const handleNoticeEnabledChange = (enabled: boolean) => {
     setSettings(prev => ({
@@ -405,6 +405,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="공지사항 알림"
                 item={settings.notice.notice}
                 onChange={(item) => handleNoticeItemChange('notice', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.notice.enabled}
               />
             )}
@@ -413,6 +414,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="이벤트 알림"
                 item={settings.notice.event}
                 onChange={(item) => handleNoticeItemChange('event', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.notice.enabled}
               />
             )}
@@ -431,6 +433,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="부가세 신고 알림"
                 item={settings.schedule.vatReport}
                 onChange={(item) => handleScheduleItemChange('vatReport', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.schedule.enabled}
               />
             )}
@@ -439,6 +442,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="종합소득세 신고 알림"
                 item={settings.schedule.incomeTaxReport}
                 onChange={(item) => handleScheduleItemChange('incomeTaxReport', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.schedule.enabled}
               />
             )}
@@ -457,6 +461,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="신규 업체 등록 알림"
                 item={settings.vendor.newVendor}
                 onChange={(item) => handleVendorItemChange('newVendor', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.vendor.enabled}
               />
             )}
@@ -465,6 +470,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="신용등급 등록 알림"
                 item={settings.vendor.creditRating}
                 onChange={(item) => handleVendorItemChange('creditRating', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.vendor.enabled}
               />
             )}
@@ -483,6 +489,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="연차 알림"
                 item={settings.attendance.annualLeave}
                 onChange={(item) => handleAttendanceItemChange('annualLeave', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.attendance.enabled}
               />
             )}
@@ -491,6 +498,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="출근 알림"
                 item={settings.attendance.clockIn}
                 onChange={(item) => handleAttendanceItemChange('clockIn', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.attendance.enabled}
               />
             )}
@@ -499,6 +507,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="지각 알림"
                 item={settings.attendance.late}
                 onChange={(item) => handleAttendanceItemChange('late', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.attendance.enabled}
               />
             )}
@@ -507,6 +516,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="결근 알림"
                 item={settings.attendance.absent}
                 onChange={(item) => handleAttendanceItemChange('absent', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.attendance.enabled}
               />
             )}
@@ -525,6 +535,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="수주 등록 알림"
                 item={settings.order.salesOrder}
                 onChange={(item) => handleOrderItemChange('salesOrder', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.order.enabled}
               />
             )}
@@ -533,6 +544,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="발주 알림"
                 item={settings.order.purchaseOrder}
                 onChange={(item) => handleOrderItemChange('purchaseOrder', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.order.enabled}
               />
             )}
@@ -551,6 +563,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="결재요청 알림"
                 item={settings.approval.approvalRequest}
                 onChange={(item) => handleApprovalItemChange('approvalRequest', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.approval.enabled}
               />
             )}
@@ -559,6 +572,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="기안 > 승인 알림"
                 item={settings.approval.draftApproved}
                 onChange={(item) => handleApprovalItemChange('draftApproved', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.approval.enabled}
               />
             )}
@@ -567,6 +581,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="기안 > 반려 알림"
                 item={settings.approval.draftRejected}
                 onChange={(item) => handleApprovalItemChange('draftRejected', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.approval.enabled}
               />
             )}
@@ -575,6 +590,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="기안 > 완료 알림"
                 item={settings.approval.draftCompleted}
                 onChange={(item) => handleApprovalItemChange('draftCompleted', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.approval.enabled}
               />
             )}
@@ -593,6 +609,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="안전재고 알림"
                 item={settings.production.safetyStock}
                 onChange={(item) => handleProductionItemChange('safetyStock', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.production.enabled}
               />
             )}
@@ -601,6 +618,7 @@ export function NotificationSettingsManagement({ initialData }: NotificationSett
                 label="생산완료 알림"
                 item={settings.production.productionComplete}
                 onChange={(item) => handleProductionItemChange('productionComplete', item)}
+                onPlayPreview={handlePlayPreview}
                 disabled={!settings.production.enabled}
               />
             )}
diff --git a/src/components/settings/NotificationSettings/types.ts b/src/components/settings/NotificationSettings/types.ts
index a9fd013a..ca3453d0 100644
--- a/src/components/settings/NotificationSettings/types.ts
+++ b/src/components/settings/NotificationSettings/types.ts
@@ -125,6 +125,7 @@ export interface OrderItemVisibility {
   enabled: boolean;
   salesOrder: boolean; // 수주 알림
   purchaseOrder: boolean; // 발주 알림
+  approvalRequest: boolean; // 결재요청 알림
 }
 
 // 전자결재 알림 항목 설정
@@ -232,6 +233,7 @@ export const DEFAULT_ITEM_VISIBILITY: ItemVisibilitySettings = {
     enabled: true,
     salesOrder: true,
     purchaseOrder: true,
+    approvalRequest: true,
   },
   approval: {
     enabled: true,
diff --git a/src/lib/api/client.ts b/src/lib/api/client.ts
index 7f7203b1..18205aa5 100644
--- a/src/lib/api/client.ts
+++ b/src/lib/api/client.ts
@@ -178,7 +178,7 @@ export class ApiClient {
 
     const error: ApiErrorResponse = {
       message: data.message || 'An error occurred',
-      errors: data.errors,
+      errors: data.errors || data.error?.details,
       code: data.code,
     };
 
diff --git a/src/lib/api/index.ts b/src/lib/api/index.ts
index 162c8ecd..2cc382bf 100644
--- a/src/lib/api/index.ts
+++ b/src/lib/api/index.ts
@@ -174,7 +174,7 @@ class ServerApiClient {
         throw {
           status: response.status,
           message: errorData.message || 'An error occurred',
-          errors: errorData.errors,
+          errors: errorData.errors || errorData.error?.details,
           code: errorData.code,
         };
       }