fix(前端): 修复成员表头与加班导出

关键改动：

- 成员管理表格改为卡片内滚动，并固定每个表头单元格

- 加班导出按当前月份筛选导出记录

- 增加成员表头与加班导出月份过滤测试

Co-Authored-By: Codex GPT-5 <codex@openai.com>

apps/web/app/overtime/page.tsx

@@ -8,7 +8,7 @@ import { useRequirementStore } from '@/stores/useRequirementStore';
 import { useAuthStore } from '@/stores/useAuthStore';
 import { useMemberStore } from '@/stores/useMemberStore';
 import { flattenProjects, flattenVersions } from '@/lib/derive';
-import { calcDuration, filterOvertimeRecordsForViewer } from '@/lib/overtime';
+import { calcDuration, filterOvertimeRecordsForExportMonth, filterOvertimeRecordsForViewer } from '@/lib/overtime';
 import type { OvertimeRecord } from '@/lib/overtime';
 import { Pagination, usePagination } from '@/components/Pagination';
 import { DictDrawer } from '@/components/requirement/DictDrawer';
@@ -133,7 +133,9 @@ function OvertimePageContent() {
 
   const handleExport = () => {
     const header = ['项目', '版本', '加班人', '开始时间', '结束时间', '时长(h)', '加班原因', '备注'];
-    const rows = filtered.map((r) => [
+    const exportRecords = filterOvertimeRecordsForExportMonth(visibleRecords, monthFilter)
+      .sort((a, b) => new Date(b.startTime).getTime() - new Date(a.startTime).getTime());
+    const rows = exportRecords.map((r) => [
       projectName(r.projectId),
       versionName(r.versionId),
       r.person,