feat: 完成 F17 报表导出（CSV/XLSX）\n\n- 后端新增 /api/exports/* 导出接口（含权限与审计记录）\n- CSV 采用流式生成，XLSX 使用 exceljs\n- 前端在报销/票据/审计页加入导出入口（下载 Blob）\n- 更新 P5 蓝图 v3 中 F17 状态为 DONE

client/src/pages/AuditLogsPage.tsx

@@ -1,7 +1,11 @@
 import { useEffect, useMemo, useState } from "react";
 import { isApiError } from "../api/types";
+import { exportAuditLogs } from "../api/exports";
 import { fetchAuditLogs, type AuditLogListResponse } from "../api/audit";
 import { PageHeader } from "../components/common/PageHeader";
+import { Button } from "../components/ui/button";
+import { DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuTrigger } from "../components/ui/dropdown-menu";
+import { downloadBlob } from "../lib/download";
 
 const DEFAULT_PAGE_SIZE = 20;
 
@@ -10,6 +14,7 @@ export function AuditLogsPage() {
   const [actionFilter, setActionFilter] = useState("");
   const [targetTypeFilter, setTargetTypeFilter] = useState("");
   const [loading, setLoading] = useState(false);
+  const [exporting, setExporting] = useState(false);
   const [error, setError] = useState("");
   const [data, setData] = useState<AuditLogListResponse | null>(null);
 
@@ -63,7 +68,71 @@ export function AuditLogsPage() {
 
   return (
     <div>
-      <PageHeader title="审计工作台" subtitle="只读查看系统关键操作审计记录。" />
+      <PageHeader
+        title="审计工作台"
+        subtitle="只读查看系统关键操作审计记录。"
+        actions={
+          <DropdownMenu>
+            <DropdownMenuTrigger asChild>
+              <Button variant="secondary" type="button" disabled={exporting} data-testid="audit-export">
+                {exporting ? "导出中..." : "导出"}
+              </Button>
+            </DropdownMenuTrigger>
+            <DropdownMenuContent align="end">
+              <DropdownMenuItem
+                data-testid="audit-export-csv"
+                onSelect={async () => {
+                  setExporting(true);
+                  try {
+                    const response = await exportAuditLogs({
+                      format: "csv",
+                      action: actionFilter || undefined,
+                      targetType: targetTypeFilter || undefined,
+                    });
+                    downloadBlob(response.blob, response.filename ?? "audit-logs.csv");
+                    setError("");
+                  } catch (err) {
+                    if (isApiError(err)) {
+                      setError(`${err.code}: ${err.message}`);
+                    } else {
+                      setError("导出审计日志失败，请稍后重试");
+                    }
+                  } finally {
+                    setExporting(false);
+                  }
+                }}
+              >
+                导出 CSV
+              </DropdownMenuItem>
+              <DropdownMenuItem
+                data-testid="audit-export-xlsx"
+                onSelect={async () => {
+                  setExporting(true);
+                  try {
+                    const response = await exportAuditLogs({
+                      format: "xlsx",
+                      action: actionFilter || undefined,
+                      targetType: targetTypeFilter || undefined,
+                    });
+                    downloadBlob(response.blob, response.filename ?? "audit-logs.xlsx");
+                    setError("");
+                  } catch (err) {
+                    if (isApiError(err)) {
+                      setError(`${err.code}: ${err.message}`);
+                    } else {
+                      setError("导出审计日志失败，请稍后重试");
+                    }
+                  } finally {
+                    setExporting(false);
+                  }
+                }}
+              >
+                导出 Excel
+              </DropdownMenuItem>
+            </DropdownMenuContent>
+          </DropdownMenu>
+        }
+      />
 
       <section className="card-std space-y-4">
         <div className="grid gap-3 md:grid-cols-3">