feat: 支持单套试卷同一提交人多次刷卷并展示

- DataService::build 新增 aggregateByStudent 按学号聚合：
  dedupe=true 仅保留最新一份；false 则每学号一行（代表成绩取最高分）
  附 attempts(次数) 与 attempts_list(每次提交明细)，修正提交人数被多次提交inflate的问题
- api.php dashboard 透传 attempts/attempts_list；statOf 增加 attempts 求和；export 增加刷题次数列
- dashboard.php 成员榜加"刷N次"徽标，点击下钻弹窗看每次提交（时间/成绩/时长/暂存）；hero 显示总提交次数
- 主统计页成绩明细同样加"刷N次"徽标与下钻弹窗
- stats 新增 attempts_total

dashboard.php

@@ -71,7 +71,21 @@ if (!ny_is_auth()) {
 
 </div>
 
+<!-- 多次刷题明细弹窗 -->
+<div class="modal" id="attemptsModal">
+  <div class="modal-box">
+    <div class="modal-head"><h3 id="attTitle">提交明细</h3><button class="x" data-close onclick="closeAttempts()">&times;</button></div>
+    <div class="modal-body" id="attBody"></div>
+  </div>
+</div>
+
 <script>
+// 弹窗：点击遮罩或带 data-close 的元素关闭
+document.querySelectorAll('.modal').forEach(m => {
+  m.addEventListener('click', e => {
+    if (e.target === m || e.target.hasAttribute('data-close')) m.classList.remove('open');
+  });
+});
 const $ = s => document.querySelector(s);
 function esc(s){ return String(s == null ? '' : s).replace(/[&<>"]/g, c => ({'&':'&amp;','<':'&lt;','>':'&gt;','"':'&quot;'}[c])); }
 function rateColor(r){
@@ -204,7 +218,7 @@ async function refreshClassSel(){
   }
 }
 
-/* ---------- 成员榜 ---------- */
+/* ---------- 成员榜（含多次刷题徽标与下钻） ---------- */
 function membersTable(members){
   if (!members || !members.length) {
     return '<div class="empty" style="padding:18px 0">暂无考试成员</div>';
@@ -213,18 +227,45 @@ function membersTable(members){
     '<thead><tr><th style="width:60px">排名</th><th>姓名</th><th style="width:80px">成绩</th></tr></thead><tbody>' +
     members.map(m => {
       const rk = m.rank;
-      const badge = rk === 1 ? 'rk rk-1' : (rk === 2 ? 'rk rk-2' : (rk === 3 ? 'rk rk-3' : 'rk'));
+      const badge = rk === 1 ? 'rk rk-1' : (rk === 2 ? 'rk rk-2' : (rk === 3 ? 'rk rk-3' : 'rk');
       const sc = m.score;
       const cls = sc == null ? '' : (sc >= 90 ? 'score-high' : (sc >= 60 ? 'score-mid' : 'score-low'));
-      return '<tr>' +
+      const att = (m.attempts || 1) > 1;
+      const tag = att ? ' <span class="tag tag-att" title="查看 ' + m.attempts + ' 次提交明细">刷' + m.attempts + '次</span>' : '';
+      return '<tr' + (att ? ' class="clickable" onclick="openAttempts(' + JSON.stringify(m.sid) + ')"' : '') + '>' +
         '<td class="num"><span class="' + badge + '">' + rk + '</span></td>' +
-        '<td class="name">' + esc(m.name) + '</td>' +
+        '<td class="name">' + esc(m.name) + tag + '</td>' +
         '<td class="score num ' + cls + '">' + (sc == null ? '-' : sc) + '</td>' +
       '</tr>';
     }).join('') +
     '</tbody></table></div>';
 }
 
+/* ---------- 多次刷题下钻弹窗 ---------- */
+function openAttempts(sid){
+  const info = (window.MEMBER_ATT || {})[sid];
+  if (!info) return;
+  const list = info.list || [];
+  const rows = list.map(a => {
+    const sc = a.score == null ? '<span class="muted">未判分</span>' : esc(a.score);
+    const tmp = a.temp_save ? ' <span class="tag tag-gray">暂存</span>' : '';
+    return '<tr>' +
+      '<td class="num">' + esc(a.submit_at) + '</td>' +
+      '<td class="num">' + sc + tmp + '</td>' +
+      '<td class="num">' + esc(a.duration_txt || '-') + '</td>' +
+    '</tr>';
+  }).join('');
+  $('#attTitle').textContent = info.name + ' · 共 ' + (info.attempts || list.length) + ' 次提交';
+  $('#attBody').innerHTML = list.length
+    ? '<table class="grid compact"><thead><tr><th>提交时间</th><th>成绩</th><th>考试时长</th></tr></thead><tbody>' + rows + '</tbody></table>'
+    : '<div class="empty">无提交明细</div>';
+  document.querySelector('#attemptsModal').classList.add('open');
+}
+function closeAttempts(){
+  const m = document.querySelector('#attemptsModal');
+  if (m) m.classList.remove('open');
+}
+
 /* ---------- 渲染单班看板 ---------- */
 function renderBoard(){
   const pid = $('#projectSel').value;
@@ -252,8 +293,21 @@ function renderBoard(){
   // 顶部品牌区：动态标题
   const projectName = ($('#projectSel').selectedOptions[0] || {}).textContent || '';
   $('#heroTitle').textContent = cls + ' · 班级看板';
+
+  // 构建"学号 -> 多次刷题明细"映射（班级级 members 已含全班所有人的 attempts_list）
+  const MAP = {};
+  (c.members || []).forEach(m => {
+    if ((m.attempts || 1) > 1) {
+      MAP[m.sid] = { name: m.name, attempts: m.attempts, list: m.attempts_list || [] };
+    }
+  });
+  window.MEMBER_ATT = MAP;
+
+  const overall = DASH.overall || {};
+  const totalAttempts = (overall.attempts_total || 0);
   $('#heroSub').textContent = '问卷：' + projectName.replace(/\uff08\d+份\uff09$/, '') + ' · ' +
-    '总 ' + c.total + ' / 已交 ' + c.submitted + ' / 缺考 ' + c.absent;
+    '总 ' + c.total + ' / 已交 ' + c.submitted + ' / 缺考 ' + c.absent +
+    (totalAttempts ? ' · 共 ' + totalAttempts + ' 次提交' : '');
 
   // 6 卡汇总
   const color = rateColor(c.rate || 0);
@@ -271,7 +325,8 @@ function renderBoard(){
     box.innerHTML = '<div class="gpanel">' +
       '<div class="ghead"><strong>本班考试成员</strong>' +
       '<span class="rate-num">' + c.submitted + ' 人</span></div>' +
-      '<div class="sub">该班级未设置分组（A/B），以下按成绩从高到低排列</div>' +
+      '<div class="sub">该班级未设置分组（A/B），以下按成绩从高到低排列' +
+      (c.attempts > c.submitted ? ' · 共 ' + c.attempts + ' 次刷题' : '') + '</div>' +
       membersTable(c.members) + '</div>';
   } else {
     box.innerHTML = '<div class="group-compare">' + groups.map(g => {
@@ -279,7 +334,8 @@ function renderBoard(){
       return '<div class="gpanel">' +
         '<div class="ghead"><strong>' + esc(g.group) + ' 组</strong>' +
         '<span class="rate-num" style="color:' + gc + '">' + g.rate + '%</span></div>' +
-        '<div class="sub">已提交 ' + g.submitted + ' / 总人数 ' + g.total + ' · 缺考 ' + g.absent + '</div>' +
+        '<div class="sub">已提交 ' + g.submitted + ' / 总人数 ' + g.total + ' · 缺考 ' + g.absent +
+        (g.attempts > g.submitted ? ' · 共 ' + g.attempts + ' 次刷题' : '') + '</div>' +
         '<div class="bar"><i style="width:' + g.rate + '%;background:' + gc + '"></i></div>' +
         '<div class="class-metrics">' +
           '<div class="m"><span>平均分</span><b>' + (g.avg != null ? g.avg : '-') + '</b></div>' +