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/production/WorkOrders/AssigneeSelectModal.tsx

@@ -9,7 +9,7 @@
 
 import { useState, useEffect, useMemo } from 'react';
 import { Check, X, ChevronDown, ChevronRight } from 'lucide-react';
-import { ContentLoadingSpinner } from '@/components/ui/loading-spinner';
+import { ContentSkeleton } from '@/components/ui/skeleton';
 import { Button } from '@/components/ui/button';
 import { Checkbox } from '@/components/ui/checkbox';
 import {
@@ -290,7 +290,7 @@ export function AssigneeSelectModal({
         {/* 컨텐츠 영역 */}
         <div className="max-h-[400px] overflow-y-auto">
           {loading ? (
-            <ContentLoadingSpinner text="부서 목록을 불러오는 중..." />
+            <ContentSkeleton type="list" rows={6} />
           ) : error ? (
             <div className="flex flex-col items-center justify-center py-12 text-center">
               <p className="text-red-500 mb-2">{error}</p>

src/components/production/WorkOrders/SalesOrderSelectModal.tsx

@@ -7,7 +7,7 @@
 
 import { useState, useEffect, useCallback } from 'react';
 import { Search, FileText } from 'lucide-react';
-import { ContentLoadingSpinner } from '@/components/ui/loading-spinner';
+import { ContentSkeleton } from '@/components/ui/skeleton';
 import {
   Dialog,
   DialogContent,
@@ -121,7 +121,7 @@ export function SalesOrderSelectModal({
         {/* 수주 목록 */}
         <div className="max-h-[400px] overflow-y-auto space-y-2">
           {isLoading ? (
-            <ContentLoadingSpinner text="수주 목록을 불러오는 중..." />
+            <ContentSkeleton type="cards" rows={4} />
           ) : salesOrders.map((order) => (
             <div
               key={order.id}

src/components/production/WorkOrders/WorkOrderCreate.tsx

@@ -513,6 +513,7 @@ export function WorkOrderCreate() {
       <IntegratedDetailTemplate
         config={workOrderCreateConfig}
         mode="create"
+        isLoading={isLoadingProcesses}
         isSubmitting={isSubmitting}
         onBack={handleCancel}
         onCancel={handleCancel}