refactor: UniversalListPage externalIsLoading 지원 및 스켈레톤 개선

- UniversalListPage에 externalIsLoading prop 추가
- CardTransactionDetailClient DevFill 자동입력 기능 추가
- 여러 컴포넌트 로딩 상태 처리 개선
- skeleton 컴포넌트 확장

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/approval/ApprovalBox/index.tsx

@@ -810,6 +810,7 @@ export function ApprovalBox() {
       onTabChange={handleTabChange}
       onSearchChange={setSearchQuery}
       onFilterChange={handleMobileFilterChange}
+      externalIsLoading={isLoading}
     />
   );
 }

src/components/approval/DocumentCreate/ExpenseEstimateForm.tsx

@@ -1,7 +1,7 @@
 'use client';
 
 import { Fragment } from 'react';
-import { ContentLoadingSpinner } from '@/components/ui/loading-spinner';
+import { ContentSkeleton } from '@/components/ui/skeleton';
 import { Checkbox } from '@/components/ui/checkbox';
 import {
   Table,
@@ -63,7 +63,7 @@ export function ExpenseEstimateForm({ data, onChange, isLoading }: ExpenseEstima
       <div className="space-y-6">
         <div className="bg-white rounded-lg border p-6">
           <h3 className="text-lg font-semibold mb-4">지출 예상 내역서 목록</h3>
-          <ContentLoadingSpinner text="항목을 불러오는 중..." />
+          <ContentSkeleton type="table" rows={5} />
         </div>
       </div>
     );

src/components/approval/DraftBox/index.tsx

@@ -776,6 +776,7 @@ export function DraftBox() {
       }}
       onSearchChange={setSearchQuery}
       onFilterChange={handleFilterChange}
+      externalIsLoading={isLoading}
     />
   );
 }

src/components/approval/ReferenceBox/index.tsx

@@ -671,6 +671,7 @@ export function ReferenceBox() {
       onTabChange={handleTabChange}
       onSearchChange={setSearchQuery}
       onFilterChange={handleMobileFilterChange}
+      externalIsLoading={isLoading}
     />
   );
 }