feat: 견적 품목 추가 시 단가 자동 조회 기능

- fetchItemPrices 클라이언트 API 함수 추가 (items.ts)
- 품목 선택 시 /api/proxy/quotes/items/prices를 통해 단가 조회
- 조회된 단가로 견적금액요약에 즉시 반영

src/components/quotes/LocationDetailPanel.tsx

@@ -12,6 +12,7 @@
 import { useState, useMemo, useEffect } from "react";
 import { Package, Settings, Plus, Trash2, Loader2, Calculator, Save } from "lucide-react";
 import { getItemCategoryTree, type ItemCategoryNode } from "./actions";
+import { fetchItemPrices } from "@/lib/api/items";
 
 import { Badge } from "../ui/badge";
 import { Button } from "../ui/button";
@@ -724,21 +725,32 @@ export function LocationDetailPanel({
       <ItemSearchModal
         open={itemSearchOpen}
         onOpenChange={setItemSearchOpen}
-        onSelectItem={(item) => {
+        onSelectItem={async (item) => {
           if (!location) return;
 
           const currentTab = detailTabs.find((t) => t.value === activeTab);
           const categoryCode = activeTab;
           const categoryLabel = currentTab?.label || activeTab;
 
+          // 단가 조회 (클라이언트 API 호출)
+          let unitPrice = 0;
+          try {
+            const priceResult = await fetchItemPrices([item.code]);
+            unitPrice = priceResult[item.code]?.unit_price || 0;
+          } catch (error) {
+            console.error('[품목 추가] 단가 조회 실패:', error);
+          }
+
+          const totalPrice = unitPrice * 1; // quantity = 1
+
           const newItem: BomCalculationResultItem & { category_code?: string; is_manual?: boolean } = {
             item_code: item.code,
             item_name: item.name,
             specification: item.specification || "",
             unit: "EA",
             quantity: 1,
-            unit_price: 0,
-            total_price: 0,
+            unit_price: unitPrice,
+            total_price: totalPrice,
             process_group: categoryLabel,
             category_code: categoryCode,
             is_manual: true,
@@ -789,8 +801,13 @@ export function LocationDetailPanel({
             grand_total: updatedGrandTotal,
           };
 
-          onUpdateLocation(location.id, { bomResult: updatedBomResult });
-          console.log(`[품목 추가] ${item.code} - ${item.name} → ${categoryLabel} (${categoryCode})`);
+          // unitPrice, totalPrice도 함께 업데이트
+          onUpdateLocation(location.id, {
+            bomResult: updatedBomResult,
+            unitPrice: updatedGrandTotal,
+            totalPrice: updatedGrandTotal * location.quantity,
+          });
+          console.log(`[품목 추가] ${item.code} - ${item.name} → ${categoryLabel} (${categoryCode}), 단가: ${unitPrice}`);
         }}
         tabLabel={detailTabs.find((t) => t.value === activeTab)?.label}
       />