feat: 完善/优化/新增大批次 + 安全加固 + 性能优化

- 修复再次提交不置顶（排序键改用 last_submit_ts）
- 后端结果缓存 + 并发锁（DataCache / ny_build_data / Roster 指纹失效）
- 导出 xlsx 多表：按最新成绩 / 按班级分表 / 可选列
- 名单管理：新增改弹窗、删除多选+二次确认、登陆账号列
- 安全：CSRF token + 登录失败限流（5次锁10分钟）
- 未匹配答卷一键加入名单（unmatched_map）
- 缺考名单增强：复制学号/姓名、按班统计、打印
- 成绩快照 + 跨卷趋势（Snapshot）
- 异常检测线索（短时长高分/高频重考/雷同成绩）
- 前端性能：虚拟滚动、搜索防抖、后台暂停、失败退避
- 测试沉淀：test-new-features.php + run-all.sh

index.php

@@ -79,7 +79,7 @@ $rosterCount = Roster::count();
       <label>搜索</label>
       <input type="text" id="kw" placeholder="输入学号或姓名筛选">
     </div>
-    <div class="field btns">
+    <div class="field btns" style="flex-wrap:wrap;gap:8px">
       <label style="display:flex;align-items:center;gap:6px;font-size:12px;color:var(--text-2)">导出排序
         <select id="exportSortSel" style="height:30px;border-radius:8px;border:1px solid var(--border);padding:0 6px;background:#fff">
           <option value="time">按提交时间</option>
@@ -88,8 +88,17 @@ $rosterCount = Roster::count();
           <option value="score_asc">按成绩升序</option>
         </select>
       </label>
+      <label style="display:flex;align-items:center;gap:4px;font-size:12px;color:var(--text-2);cursor:pointer" title="每人只导一行：最近一次成绩 + 最高分 + 考试次数">
+        <input type="checkbox" id="exportLatest" style="width:auto;height:auto">按最新成绩
+      </label>
+      <label style="display:flex;align-items:center;gap:4px;font-size:12px;color:var(--text-2);cursor:pointer" title="按班级拆分多个工作表（xlsx 多表）">
+        <input type="checkbox" id="exportSplit" style="width:auto;height:auto">按班级分表
+      </label>
       <button class="btn" id="btnExport">导出成绩</button>
       <button class="btn" id="btnExportAbsent">导出缺考</button>
+      <button class="btn" id="btnSnapshot" title="保存当前成绩为一份带标签的时间点快照">存快照</button>
+      <button class="btn" id="btnTrend" title="查看本卷各快照间每名学生的成绩趋势">趋势</button>
+      <button class="btn" id="btnAnomaly" title="异常检测线索：短时长高分 / 高频重考 / 雷同成绩">异常</button>
     </div>
   </section>
 
@@ -133,9 +142,15 @@ $rosterCount = Roster::count();
     </section>
 
     <section class="panel" id="absentPanel">
-      <div class="panel-head"><h2>缺考名单 <small id="absentHint"></small></h2></div>
+      <div class="panel-head">
+        <h2>缺考名单 <small id="absentHint"></small></h2>
+        <span class="spacer"></span>
+        <button class="btn sm" id="btnCopySids" title="复制全部缺考学号（逗号分隔）">复制学号</button>
+        <button class="btn sm" id="btnCopyNames" title="复制全部缺考姓名">复制姓名</button>
+        <button class="btn sm" id="btnPrintAbsent" title="打印缺考名单">打印</button>
+      </div>
       <div class="table-scroll short">
-        <table class="grid compact">
+        <table class="grid compact" id="absentTable">
           <thead><tr><th>学号</th><th>姓名</th><th>班级</th><th>组别</th></tr></thead>
           <tbody id="absentBody"><tr><td colspan="4" class="empty">—</td></tr></tbody>
         </table>
@@ -146,8 +161,8 @@ $rosterCount = Roster::count();
       <div class="panel-head"><h2>未匹配答卷 <small>姓名不在名单中</small></h2></div>
       <div class="table-scroll short">
         <table class="grid compact">
-          <thead><tr><th>姓名</th><th>成绩</th><th>提交时间</th></tr></thead>
-          <tbody id="unmatchedBody"><tr><td colspan="3" class="empty">—</td></tr></tbody>
+          <thead><tr><th>姓名</th><th>成绩</th><th>提交时间</th><th style="width:90px">操作</th></tr></thead>
+          <tbody id="unmatchedBody"><tr><td colspan="4" class="empty">—</td></tr></tbody>
         </table>
       </div>
     </section>
@@ -178,7 +193,8 @@ $rosterCount = Roster::count();
         </div>
         <div class="fi">
           <label>每页拉取条数</label>
-          <input type="number" id="cfgPageSize" min="20" max="1000">
+          <input type="number" id="cfgPageSize" min="20" max="200">
+          <p class="hint">实际生效上限 200，超出会自动夹到 200（防止单页内存耗尽）</p>
         </div>
         <div class="fi">
           <label>默认满分（用于合格率）</label>
@@ -280,12 +296,13 @@ $rosterCount = Roster::count();
         <input type="text" id="rosterSearch" placeholder="搜索学号 / 姓名">
         <span class="spacer"></span>
         <button class="btn sm" id="btnAddRow">+ 新增</button>
+        <button class="btn sm danger" id="btnDelSel" hidden>删除选中</button>
         <button class="btn sm danger" id="btnClearRoster">清空</button>
         <button class="btn sm btn-primary" id="btnSaveRoster">保存名单</button>
       </div>
       <div class="table-scroll mid">
         <table class="grid compact" id="rosterTable">
-          <thead><tr><th style="width:28%">学号</th><th style="width:22%">姓名</th><th>班级</th><th>组别</th><th style="width:70px">操作</th></tr></thead>
+          <thead><tr><th style="width:34px"><input type="checkbox" id="rosterCheckAll" title="全选"></th><th style="width:24%">学号</th><th style="width:20%">姓名</th><th>班级</th><th>组别</th><th>登陆账号</th></tr></thead>
           <tbody id="rosterBody"></tbody>
         </table>
       </div>
@@ -306,6 +323,133 @@ $rosterCount = Roster::count();
   </div>
 </div>
 
+<!-- 新增学生弹窗 -->
+<div class="modal" id="addStudentModal">
+  <div class="modal-box">
+    <div class="modal-head"><h3>新增学生</h3><button class="x" data-close>&times;</button></div>
+    <div class="modal-body">
+      <div class="fi">
+        <label>学号 <b class="req">*</b></label>
+        <input type="text" id="addSid" placeholder="必填">
+      </div>
+      <div class="fi">
+        <label>姓名 <b class="req">*</b></label>
+        <input type="text" id="addName" placeholder="必填">
+      </div>
+      <div class="fi">
+        <label>班级</label>
+        <input type="text" id="addCls" placeholder="可选">
+      </div>
+      <div class="fi">
+        <label>组别</label>
+        <input type="text" id="addGrp" placeholder="如 A / B，可选">
+      </div>
+      <div class="fi">
+        <label>登陆账号</label>
+        <input type="text" id="addLogin" placeholder="可选，用于抽取页登录">
+      </div>
+      <p class="hint" id="addStudentHint"></p>
+    </div>
+    <div class="modal-foot">
+      <span class="spacer"></span>
+      <button class="btn" data-close>取消</button>
+      <button class="btn btn-primary" id="btnAddStudentOk">添加</button>
+    </div>
+  </div>
+</div>
+
+<!-- 未匹配答卷映射到名单 -->
+<div class="modal" id="mapUnmatchedModal">
+  <div class="modal-box">
+    <div class="modal-head"><h3>加入名单</h3><button class="x" data-close>&times;</button></div>
+    <div class="modal-body">
+      <p class="hint" style="margin:0 0 12px">答卷姓名：<b id="mapUmName"></b>（不在名单中）</p>
+      <div class="fi">
+        <label>学号 <b class="req">*</b></label>
+        <input type="text" id="mapUmSid" placeholder="输入该生的学号">
+      </div>
+      <div class="fi">
+        <label>班级</label>
+        <input type="text" id="mapUmCls" placeholder="可选">
+      </div>
+      <div class="fi">
+        <label>组别</label>
+        <input type="text" id="mapUmGrp" placeholder="可选">
+      </div>
+      <p class="hint" id="mapUmHint"></p>
+    </div>
+    <div class="modal-foot">
+      <span class="spacer"></span>
+      <button class="btn" data-close>取消</button>
+      <button class="btn btn-primary" id="btnMapUmOk">加入名单</button>
+    </div>
+  </div>
+</div>
+
+<!-- 成绩快照 / 趋势 -->
+<div class="modal" id="snapshotModal">
+  <div class="modal-box wide">
+    <div class="modal-head"><h3 id="snapTitle">成绩快照</h3><button class="x" data-close>&times;</button></div>
+    <div class="modal-body">
+      <div class="fi" style="margin-bottom:10px">
+        <label>快照标签（可选）</label>
+        <input type="text" id="snapLabel" placeholder="如：第一次考试、补考后…">
+      </div>
+      <div class="snap-toolbar" style="display:flex;gap:8px;margin-bottom:12px">
+        <button class="btn sm btn-primary" id="btnSnapSave">保存当前快照</button>
+        <span class="spacer"></span>
+        <button class="btn sm" id="btnSnapRefresh">刷新列表</button>
+        <button class="btn sm" id="btnSnapTrend">查看趋势</button>
+      </div>
+      <div class="table-scroll mid">
+        <table class="grid compact" id="snapTable">
+          <thead><tr><th>标签</th><th>保存时间</th><th>人数</th><th>项目</th><th style="width:70px">操作</th></tr></thead>
+          <tbody id="snapBody"><tr><td colspan="5" class="empty">暂无快照</td></tr></tbody>
+        </table>
+      </div>
+    </div>
+    <div class="modal-foot">
+      <span class="spacer"></span>
+      <button class="btn" data-close>关闭</button>
+    </div>
+  </div>
+</div>
+
+<!-- 跨快照趋势 -->
+<div class="modal" id="trendModal">
+  <div class="modal-box wide">
+    <div class="modal-head"><h3>成绩趋势 <small id="trendSub"></small></h3><button class="x" data-close>&times;</button></div>
+    <div class="modal-body">
+      <div class="table-scroll" style="max-height:60vh">
+        <table class="grid compact" id="trendTable">
+          <thead id="trendHead"></thead>
+          <tbody id="trendBody"><tr><td colspan="10" class="empty">加载中…</td></tr></tbody>
+        </table>
+      </div>
+      <p class="hint" id="trendHint">趋势值为每名学生的「最高分」，未出现该快照的记「—」</p>
+    </div>
+    <div class="modal-foot">
+      <span class="spacer"></span>
+      <button class="btn" data-close>关闭</button>
+    </div>
+  </div>
+</div>
+
+<!-- 异常检测线索 -->
+<div class="modal" id="anomalyModal">
+  <div class="modal-box wide">
+    <div class="modal-head"><h3>异常检测线索</h3><button class="x" data-close>&times;</button></div>
+    <div class="modal-body">
+      <p class="hint" style="margin:0 0 12px">以下为自动统计的「防作弊线索」，仅供人工复核判断，不代表结论。</p>
+      <div id="anomalyBody"></div>
+    </div>
+    <div class="modal-foot">
+      <span class="spacer"></span>
+      <button class="btn" data-close>关闭</button>
+    </div>
+  </div>
+</div>
+
 <script>
 window.NY = {
   appName: <?= json_encode(NY_APP_NAME, JSON_UNESCAPED_UNICODE) ?>,