Initial commit: IT센터 출입자관리시스템 (ACS)

방문자 사전신청·승인, 입·출입 체크인/아웃, QR 배지, 재실현황,
블랙리스트, 대시보드 통계, 방문 리포트(엑셀)까지 7단계 전 기능 구현.

- backend: Spring Boot 3.4.5 / Java 21 (JDK 26 빌드), 세션 인증, JPA, H2/PostgreSQL, POI, ZXing, Flyway
- frontend: React 19 / Vite 6 / TypeScript
- infra: Docker Compose (db·app·web nginx), Flyway V1__init, Python 사용자 시드
- docs: 워크플로우 / 시퀀스 다이어그램(Mermaid) / 이슈·유의사항

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/pages/ReportPage.tsx

@@ -0,0 +1,50 @@
+import React, { useState } from 'react';
+import { reportDownloadUrl } from '../api';
+
+function todayISO(): string {
+  return new Date().toISOString().slice(0, 10);
+}
+function monthAgoISO(): string {
+  const d = new Date();
+  d.setMonth(d.getMonth() - 1);
+  return d.toISOString().slice(0, 10);
+}
+
+export const ReportPage: React.FC = () => {
+  const [from, setFrom] = useState(monthAgoISO());
+  const [to, setTo] = useState(todayISO());
+
+  const onDownload = () => {
+    // Trigger a download in-place via a temporary anchor. Using window.open left
+    // a blank tab behind (the .xlsx response has no HTML to render). The anchor's
+    // download attribute makes the browser save the file without navigating away.
+    // Same-origin, so the session cookie is sent automatically (dev proxy / nginx).
+    const a = document.createElement('a');
+    a.href = reportDownloadUrl(from, to);
+    a.download = `visits_${from}_${to}.xlsx`;
+    document.body.appendChild(a);
+    a.click();
+    a.remove();
+  };
+
+  return (
+    <div>
+      <div className="page-head"><h2>방문 리포트</h2></div>
+
+      <div className="card">
+        <p className="muted">기간을 선택하고 엑셀(.xlsx) 파일로 내려받습니다. (방문 시작일 기준)</p>
+        <div className="report-row">
+          <label className="field">
+            <span>시작일</span>
+            <input type="date" value={from} onChange={(e) => setFrom(e.target.value)} />
+          </label>
+          <label className="field">
+            <span>종료일</span>
+            <input type="date" value={to} onChange={(e) => setTo(e.target.value)} />
+          </label>
+          <button className="btn-primary" onClick={onDownload}>엑셀 다운로드</button>
+        </div>
+      </div>
+    </div>
+  );
+};