feat: show change timestamps in history compare

legacy/static/organization.css

@@ -862,6 +862,10 @@ body {
   width: 82px;
 }
 
+.col-compare-date {
+  width: 132px;
+}
+
 .col-compare-category {
   width: 120px;
 }

legacy/static/organization.js

@@ -1479,6 +1479,23 @@ function getListSearchEntries() {
   }));
 }
 
+function formatCompareChangedAt(value) {
+  const raw = String(value || '').trim();
+  if (!raw) {
+    return '-';
+  }
+  const date = new Date(raw);
+  if (Number.isNaN(date.getTime())) {
+    return raw;
+  }
+  const year = date.getFullYear();
+  const month = pad(date.getMonth() + 1);
+  const day = pad(date.getDate());
+  const hours = pad(date.getHours());
+  const minutes = pad(date.getMinutes());
+  return `${year}-${month}-${day} ${hours}:${minutes}`;
+}
+
 function renderListViewCompareTable() {
   const container = document.getElementById('list-table-container');
   if (!container) {
@@ -1492,6 +1509,7 @@ function renderListViewCompareTable() {
         <tr>
           <th class="col-name">이름</th>
           <th class="col-compare-status">상태</th>
+          <th class="col-compare-date">변경일시</th>
           <th class="col-compare-category">변경유형</th>
           <th>이전</th>
           <th>현재</th>
@@ -1501,7 +1519,7 @@ function renderListViewCompareTable() {
   `;
 
   if (!rows.length) {
-    html += '<tr><td colspan="5" class="list-empty-cell">선택한 기간 사이의 구성원 변경 내역이 없습니다.</td></tr>';
+    html += '<tr><td colspan="6" class="list-empty-cell">선택한 기간 사이의 구성원 변경 내역이 없습니다.</td></tr>';
   } else {
     rows.forEach((item) => {
       const categories = (item.categories || []).map((category) => `<span class="list-compare-chip">${escapeHtml(category)}</span>`).join('');
@@ -1511,6 +1529,7 @@ function renderListViewCompareTable() {
         <tr id="list-compare-row-${item.member_id}">
           <td class="font-black text-slate-700">${escapeHtml(item.name || '-')}</td>
           <td><span class="list-compare-status list-compare-status-${escapeHtml(item.status || 'updated')}">${escapeHtml(item.status_label || '-')}</span></td>
+          <td>${escapeHtml(formatCompareChangedAt(item.changed_at))}</td>
           <td><div class="list-compare-chip-group">${categories || '<span class="text-slate-300">-</span>'}</div></td>
           <td class="list-compare-cell">${beforeLines}</td>
           <td class="list-compare-cell">${afterLines}</td>