fix: 修复批量导入义工号/工作组丢失 + 新增批量删除

- 批量解析：移除义工号强制纯数字校验（原 volunteerLooksLikeNo 逻辑错误导致 VOL-003、2024-A 等全部置空）；改为列数驱动：3列时智能探测是否工作组命中，4+列保留义工号原值、剩余段统一合并为工作组解析
- 后端 batch：user_groups 插入语句改为事务内按用户编译；义工号判断改为 null/undefined 严格检查，避免真值判断丢弃空字符串或 0 开头的值
- 新增 DELETE /users/batch：事务性批量删除部员（含 user_groups/hours 级联），返回实际删除 count
- 前端列表新增复选框列（表头 indeterminate 半选态），选中 1+ 条后工具栏显示「删除选中（N）」红色按钮，确认弹窗二次校验

client/src/api/index.ts

@@ -65,6 +65,12 @@ export const usersApi = {
       failed: number;
       results: Array<{ idx: number; ok: boolean; id?: number; error?: string; item: any }>;
     }>('/users/batch', { items }).then(r => r.data),
+  batchRemove: (ids: number[]) =>
+    api.request<{ ok: boolean; deleted: number; total: number }>({
+      url: '/users/batch',
+      method: 'DELETE',
+      data: { ids },
+    }).then(r => r.data),
 };
 
 export const activitiesApi = {

client/src/pages/admin/Users.tsx

@@ -103,6 +103,8 @@ export default function Users() {
   const [batchText, setBatchText] = useState('');
   const [batchErrors, setBatchErrors] = useState<string>('');
 
+  const [selectedIds, setSelectedIds] = useState<Set<number>>(new Set());
+
   const load = async () => {
     setLoading(true);
     try {
@@ -136,6 +138,41 @@ export default function Users() {
     );
   });
 
+  const filteredIds = filtered.map((u) => u.id);
+  const allSelected = filteredIds.length > 0 && filteredIds.every((id) => selectedIds.has(id));
+  const someSelected = filteredIds.some((id) => selectedIds.has(id));
+  const selectedCount = selectedIds.size;
+
+  const toggleSelectAll = () => {
+    const next = new Set(selectedIds);
+    if (allSelected) {
+      for (const id of filteredIds) next.delete(id);
+    } else {
+      for (const id of filteredIds) next.add(id);
+    }
+    setSelectedIds(next);
+  };
+  const toggleSelectOne = (id: number) => {
+    const next = new Set(selectedIds);
+    if (next.has(id)) next.delete(id);
+    else next.add(id);
+    setSelectedIds(next);
+  };
+  const clearSelection = () => setSelectedIds(new Set());
+
+  const batchDelete = async () => {
+    if (selectedCount === 0) return;
+    if (!confirm(`确认删除选中的 ${selectedCount} 名部员？相关的时长登记也会一并删除，此操作不可撤销。`)) return;
+    try {
+      const result = await usersApi.batchRemove(Array.from(selectedIds));
+      alert(`批量删除完成：共提交 ${result.total} 条，实际删除 ${result.deleted} 条`);
+      clearSelection();
+      load();
+    } catch (e) {
+      alert(errMsg(e));
+    }
+  };
+
   const openNew = () => {
     setForm(emptyForm);
     setEditId(null);
@@ -218,6 +255,11 @@ export default function Users() {
       return result;
     };
 
+    const allGroupMatch = (names: string[]): boolean => {
+      if (names.length === 0) return false;
+      return names.every((n) => groupMap.has(n));
+    };
+
     for (let i = 0; i < lines.length; i++) {
       const line = lines[i];
       if (!line.trim()) continue;
@@ -227,28 +269,42 @@ export default function Users() {
       } else {
         parts = line.split(/[,，;；]/).map((p) => p.trim());
       }
-      const [cls = '', name = '', volunteer_no = '', ...rest] = parts;
-      const groupsStr = rest.join(',');
+      const nonEmptyParts = parts.filter((p) => p.length > 0);
+
+      let cls = '';
+      let name = '';
+      let volunteer_no = '';
+      let groupsRaw = '';
+
+      if (nonEmptyParts.length >= 2) {
+        cls = parts[0] || '';
+        name = parts[1] || '';
+        if (nonEmptyParts.length === 2) {
+          volunteer_no = '';
+          groupsRaw = '';
+        } else if (nonEmptyParts.length === 3) {
+          const third = parts[2] || '';
+          const probe = splitGroupNames(third);
+          if (allGroupMatch(probe)) {
+            volunteer_no = '';
+            groupsRaw = third;
+          } else {
+            volunteer_no = third;
+            groupsRaw = '';
+          }
+        } else {
+          volunteer_no = parts[2] || '';
+          groupsRaw = parts.slice(3).join(',');
+        }
+      }
+
       const errors: string[] = [];
       if (!cls) errors.push('缺少班级');
       if (!name) errors.push('缺少姓名');
       const groupIds: number[] = [];
       const groupNames: string[] = [];
-      const rawNames = splitGroupNames([volunteer_no, groupsStr].filter(Boolean).join('/'));
-      const volunteerLooksLikeNo = /^\d+$/.test(volunteer_no.trim());
-      const realRawNames: string[] = [];
-      if (volunteer_no.trim() && !volunteerLooksLikeNo) {
-        const probe = splitGroupNames(volunteer_no);
-        const allMatch = probe.length > 0 && probe.every((n) => groupMap.has(n));
-        if (allMatch) {
-          realRawNames.push(...probe);
-        } else {
-          realRawNames.push(...splitGroupNames(groupsStr));
-        }
-      } else {
-        realRawNames.push(...splitGroupNames(groupsStr));
-      }
-      for (const n of realRawNames) {
+      const rawNames = splitGroupNames(groupsRaw);
+      for (const n of rawNames) {
         if (!n) continue;
         const gid = groupMap.get(n);
         if (gid === undefined) {
@@ -261,12 +317,11 @@ export default function Users() {
           }
         }
       }
-      const vol = volunteerLooksLikeNo ? volunteer_no : '';
       rows.push({
         idx: i,
-        class: cls || '',
-        name: name || '',
-        volunteer_no: vol,
+        class: cls,
+        name: name,
+        volunteer_no: volunteer_no,
         group_ids: groupIds,
         group_names: groupNames,
         raw: line,
@@ -331,6 +386,13 @@ export default function Users() {
           className="md:max-w-md"
         />
         <div className="flex gap-2 flex-wrap">
+          {selectedCount > 0 && (
+            <Button variant="danger" onClick={batchDelete}>
+              <span className="inline-flex items-center gap-2">
+                <IconTrash size={18} />删除选中（{selectedCount}）
+              </span>
+            </Button>
+          )}
           <Button variant="secondary" onClick={() => setBatchOpen(true)}>
             <span className="inline-flex items-center gap-2">
               <IconUsers size={18} />批量添加部员
@@ -346,6 +408,30 @@ export default function Users() {
 
       <DataTable<UserItem>
         columns={[
+          {
+            key: '__sel',
+            title: (
+              <label className="inline-flex items-center gap-2 cursor-pointer">
+                <input
+                  type="checkbox"
+                  className="accent-[#275354] w-4 h-4"
+                  checked={allSelected}
+                  ref={(el) => { if (el) el.indeterminate = !allSelected && someSelected; }}
+                  onChange={toggleSelectAll}
+                />
+                <span className="text-xs text-gray-600">{selectedCount > 0 ? `已选 ${selectedCount}` : '全选'}</span>
+              </label>
+            ),
+            width: '120px',
+            render: (r) => (
+              <input
+                type="checkbox"
+                className="accent-[#275354] w-4 h-4"
+                checked={selectedIds.has(r.id)}
+                onChange={() => toggleSelectOne(r.id)}
+              />
+            ),
+          },
           { key: 'class', title: '班级', width: '120px', render: (r) => <span className="whitespace-nowrap">{r.class}</span> },
           { key: 'name', title: '姓名', render: (r) => <span className="font-semibold">{r.name}</span> },
           { key: 'volunteer_no', title: '义工号', render: (r) => r.volunteer_no || '—' },