feat: [quality] 실적신고 확정건 엑셀 다운로드 프론트엔드 연동

- exportConfirmedExcel() 서버 액션 추가 (Blob 다운로드 패턴)
- handleExcelDownload 함수를 실제 API 호출로 변경
- 연도/분기 필터 파라미터 전달

src/components/quality/PerformanceReportManagement/PerformanceReportList.tsx

@@ -48,6 +48,7 @@ import {
   unconfirmReports,
   distributeReports,
   updateMemo,
+  exportConfirmedExcel,
 } from './actions';
 import { confirmStatusColorMap } from './mockData';
 import { isNextRedirectError } from '@/lib/utils/redirect-error';
@@ -209,9 +210,28 @@ export function PerformanceReportList() {
     }
   }, [memoSelectedIds]);
 
-  const handleExcelDownload = useCallback(() => {
-    toast.info('확정건 엑셀 다운로드 기능은 API 연동 후 활성화됩니다.');
-  }, []);
+  const handleExcelDownload = useCallback(async () => {
+    const quarterNum = quarter === '전체' ? Math.ceil(new Date().getMonth() / 3) || 1 : Number(quarter);
+    try {
+      const result = await exportConfirmedExcel({ year, quarter: quarterNum });
+      if (result.success && result.data) {
+        const url = URL.createObjectURL(result.data);
+        const a = document.createElement('a');
+        a.href = url;
+        a.download = result.filename || `판매실적대장_${year}년_${quarterNum}분기.xlsx`;
+        document.body.appendChild(a);
+        a.click();
+        document.body.removeChild(a);
+        URL.revokeObjectURL(url);
+        toast.success('엑셀 다운로드 완료');
+      } else {
+        toast.error(result.error || '엑셀 다운로드에 실패했습니다.');
+      }
+    } catch (error) {
+      if (isNextRedirectError(error)) throw error;
+      toast.error('엑셀 다운로드에 실패했습니다.');
+    }
+  }, [year, quarter]);
 
   // ===== 통계 카드 =====
   const stats: StatCard[] = useMemo(

src/components/quality/PerformanceReportManagement/actions.ts

@@ -7,6 +7,7 @@
  * - GET /api/v1/quality/performance-reports - 분기별 실적신고 목록
  * - GET /api/v1/quality/performance-reports/stats - 통계
  * - GET /api/v1/quality/performance-reports/missing - 누락체크 목록
+ * - GET /api/v1/quality/performance-reports/export-excel - 확정건 엑셀 다운로드
  * - PATCH /api/v1/quality/performance-reports/confirm - 선택 확정
  * - PATCH /api/v1/quality/performance-reports/unconfirm - 확정 해제
  * - PATCH /api/v1/quality/performance-reports/memo - 메모 일괄 적용
@@ -14,6 +15,7 @@
 
 import { executeServerAction } from '@/lib/api/execute-server-action';
 import { buildApiUrl } from '@/lib/api/query-params';
+import { cookies } from 'next/headers';
 import type {
   PerformanceReport,
   PerformanceReportStats,
@@ -301,3 +303,49 @@ export async function updateMemo(ids: string[], memo: string): Promise<{
   if (!result.success && USE_MOCK_FALLBACK) return { success: true };
   return { success: result.success, error: result.error, __authError: result.__authError };
 }
+
+// ===== 확정건 엑셀 다운로드 =====
+
+export async function exportConfirmedExcel(params: {
+  year: number;
+  quarter: number;
+}): Promise<{
+  success: boolean;
+  data?: Blob;
+  filename?: string;
+  error?: string;
+}> {
+  try {
+    const cookieStore = await cookies();
+    const token = cookieStore.get('access_token')?.value;
+
+    const headers: HeadersInit = {
+      'Accept': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+      'Authorization': token ? `Bearer ${token}` : '',
+      'X-API-KEY': process.env.API_KEY || '',
+    };
+
+    const url = buildApiUrl('/api/v1/quality/performance-reports/export-excel', {
+      year: params.year,
+      quarter: params.quarter,
+    });
+
+    const response = await fetch(url, { method: 'GET', headers });
+
+    if (!response.ok) {
+      return { success: false, error: `API 오류: ${response.status}` };
+    }
+
+    const blob = await response.blob();
+    const contentDisposition = response.headers.get('Content-Disposition');
+    const filenameMatch = contentDisposition?.match(/filename\*?=(?:UTF-8'')?(.+)/);
+    const filename = filenameMatch?.[1]
+      ? decodeURIComponent(filenameMatch[1])
+      : `판매실적대장_${params.year}년_${params.quarter}분기.xlsx`;
+
+    return { success: true, data: blob, filename };
+  } catch (error) {
+    if (error instanceof Error && error.message?.includes('NEXT_REDIRECT')) throw error;
+    return { success: false, error: '서버 오류가 발생했습니다.' };
+  }
+}