feat(WEB): 견적 시스템 개선, 엑셀 다운로드, PDF 생성 기능 추가

견적 시스템:
- QuoteRegistrationV2: 할인 모달, 거래명세서 모달, vatType 필드 추가
- DiscountModal: 할인율/할인금액 상호 계산 모달
- QuoteTransactionModal: 거래명세서 미리보기 모달
- LocationDetailPanel, LocationListPanel 개선

템플릿 기능:
- UniversalListPage: 엑셀 다운로드 기능 추가 (전체/선택 다운로드)
- DocumentViewer: PDF 생성 기능 개선

신규 API:
- /api/pdf/generate: Puppeteer 기반 PDF 생성 엔드포인트

UI 개선:
- 입력 컴포넌트 placeholder 스타일 개선 (opacity 50%)
- 각종 리스트 컴포넌트 정렬/필터링 개선

패키지 추가:
- html2canvas, jspdf, puppeteer, dom-to-image-more

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

src/components/items/DynamicItemForm/components/FormHeader.tsx

@@ -1,61 +1,29 @@
 'use client';
 
-import { Package, Save, X } from 'lucide-react';
-import { Button } from '@/components/ui/button';
+import { Package } from 'lucide-react';
 
 export interface FormHeaderProps {
   mode: 'create' | 'edit';
-  selectedItemType: string;
-  isSubmitting: boolean;
-  onCancel: () => void;
 }
 
 /**
- * 헤더 컴포넌트 - 기존 FormHeader와 동일한 디자인
+ * 헤더 컴포넌트 - 타이틀만 표시 (버튼은 하단 sticky로 이동)
  */
 export function FormHeader({
   mode,
-  selectedItemType,
-  isSubmitting,
-  onCancel,
 }: FormHeaderProps) {
   return (
-    <div className="flex flex-col md:flex-row md:items-center justify-between gap-4">
-      <div className="flex items-start gap-3">
-        <div className="p-2 bg-primary/10 rounded-lg hidden md:block">
-          <Package className="w-6 h-6 text-primary" />
-        </div>
-        <div>
-          <h1 className="text-xl md:text-2xl">
-            {mode === 'create' ? '품목 등록' : '품목 수정'}
-          </h1>
-          <p className="text-sm text-muted-foreground mt-1">
-            품목 정보를 입력하세요
-          </p>
-        </div>
+    <div className="flex items-start gap-3">
+      <div className="p-2 bg-primary/10 rounded-lg hidden md:block">
+        <Package className="w-6 h-6 text-primary" />
       </div>
-
-      <div className="flex gap-1 sm:gap-2">
-        <Button
-          type="button"
-          variant="outline"
-          size="sm"
-          onClick={onCancel}
-          className="gap-1 sm:gap-2"
-          disabled={isSubmitting}
-        >
-          <X className="h-4 w-4" />
-          <span className="hidden sm:inline">취소</span>
-        </Button>
-        <Button
-          type="submit"
-          size="sm"
-          disabled={!selectedItemType || isSubmitting}
-          className="gap-1 sm:gap-2"
-        >
-          <Save className="h-4 w-4" />
-          <span className="hidden sm:inline">{isSubmitting ? '저장 중...' : '저장'}</span>
-        </Button>
+      <div>
+        <h1 className="text-xl md:text-2xl">
+          {mode === 'create' ? '품목 등록' : '품목 수정'}
+        </h1>
+        <p className="text-sm text-muted-foreground mt-1">
+          품목 정보를 입력하세요
+        </p>
       </div>
     </div>
   );

src/components/items/DynamicItemForm/index.tsx

@@ -9,6 +9,9 @@
 import { useState, useEffect, useMemo } from 'react';
 import { useRouter } from 'next/navigation';
 import { cn } from '@/lib/utils';
+import { useMenuStore } from '@/store/menuStore';
+import { Save, X } from 'lucide-react';
+import { Button } from '@/components/ui/button';
 import { Label } from '@/components/ui/label';
 import { Input } from '@/components/ui/input';
 import { FormSectionSkeleton } from '@/components/ui/skeleton';
@@ -45,6 +48,7 @@ export default function DynamicItemForm({
   onSubmit,
 }: DynamicItemFormProps) {
   const router = useRouter();
+  const sidebarCollapsed = useMenuStore((state) => state.sidebarCollapsed);
 
   // 품목 유형 상태 (변경 가능)
   const [selectedItemType, setSelectedItemType] = useState<ItemType | ''>(initialItemType || '');
@@ -658,17 +662,12 @@ export default function DynamicItemForm({
     : [];
 
   return (
-    <form onSubmit={handleFormSubmit} className="space-y-6">
+    <form onSubmit={handleFormSubmit} className="space-y-6 pb-24">
       {/* Validation 에러 Alert */}
       <ValidationAlert errors={errors} />
 
       {/* 헤더 */}
-      <FormHeader
-        mode={mode}
-        selectedItemType={selectedItemType}
-        isSubmitting={isSubmitting}
-        onCancel={() => router.back()}
-      />
+      <FormHeader mode={mode} />
 
       {/* 기본 정보 - 목업과 동일한 레이아웃 (모든 필드 한 줄씩) */}
       <Card>
@@ -1045,6 +1044,26 @@ export default function DynamicItemForm({
         onCancel={handleCancelDuplicate}
         onGoToEdit={handleGoToEditDuplicate}
       />
+
+      {/* 하단 액션 버튼 (sticky) */}
+      <div className={`fixed bottom-6 ${sidebarCollapsed ? 'left-[156px]' : 'left-[316px]'} right-[48px] px-6 py-3 bg-background/95 backdrop-blur rounded-xl border shadow-lg z-50 transition-all duration-300 flex items-center justify-between`}>
+        <Button
+          type="button"
+          variant="outline"
+          onClick={() => router.back()}
+          disabled={isSubmitting}
+        >
+          <X className="h-4 w-4 mr-2" />
+          취소
+        </Button>
+        <Button
+          type="submit"
+          disabled={!selectedItemType || isSubmitting}
+        >
+          <Save className="h-4 w-4 mr-2" />
+          {isSubmitting ? '저장 중...' : '저장'}
+        </Button>
+      </div>
     </form>
   );
 }