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/ReimbursementsPage.tsx

@@ -4,12 +4,15 @@ import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { isApiError } from "../api/types";
 import { mapApiErrorMessage } from "../api/errorMessages";
 import { fetchMyDelegations } from "../api/delegations";
+import { exportReimbursements } from "../api/exports";
 import { createReimbursement, fetchReimbursements, type ReimbursementStatus } from "../api/reimbursements";
 import { useAuth } from "../auth/AuthContext";
 import { hasPermission } from "../auth/permissions";
+import { downloadBlob } from "../lib/download";
 import { PageHeader } from "../components/common/PageHeader";
 import { Button } from "../components/ui/button";
 import { Card } from "../components/ui/card";
+import { DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuTrigger } from "../components/ui/dropdown-menu";
 import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "../components/ui/table";
 import { Tabs, TabsList, TabsTrigger } from "../components/ui/tabs";
 
@@ -19,6 +22,7 @@ export function ReimbursementsPage() {
   const [searchParams, setSearchParams] = useSearchParams();
   const { permissions, me } = useAuth();
   const queryClient = useQueryClient();
+  const [exportError, setExportError] = useState("");
 
   const status = (searchParams.get("status") as ReimbursementStatus | null) ?? "draft";
   const page = Number(searchParams.get("page") ?? "1") || 1;
@@ -51,6 +55,21 @@ export function ReimbursementsPage() {
     },
   });
 
+  const exportMutation = useMutation({
+    mutationFn: (format: "csv" | "xlsx") => exportReimbursements({ format, status, scope }),
+    onSuccess: (response, format) => {
+      downloadBlob(response.blob, response.filename ?? `reimbursements.${format}`);
+      setExportError("");
+    },
+    onError: (err) => {
+      if (isApiError(err)) {
+        setExportError(`${err.code}: ${mapApiErrorMessage(err.code, err.details, err.message)}`);
+        return;
+      }
+      setExportError(err instanceof Error ? err.message : "导出失败");
+    },
+  });
+
   const totalPages = Math.max(1, Math.ceil((listQuery.data?.total ?? 0) / PAGE_SIZE));
 
   return (
@@ -86,6 +105,33 @@ export function ReimbursementsPage() {
             >
               {createMutation.isPending ? "创建中..." : "新建报销"}
             </Button>
+
+            <DropdownMenu>
+              <DropdownMenuTrigger asChild>
+                <Button
+                  data-testid="reimbursements-export"
+                  variant="secondary"
+                  type="button"
+                  disabled={exportMutation.isPending}
+                >
+                  {exportMutation.isPending ? "导出中..." : "导出"}
+                </Button>
+              </DropdownMenuTrigger>
+              <DropdownMenuContent align="end">
+                <DropdownMenuItem
+                  data-testid="reimbursements-export-csv"
+                  onSelect={() => exportMutation.mutate("csv")}
+                >
+                  导出 CSV
+                </DropdownMenuItem>
+                <DropdownMenuItem
+                  data-testid="reimbursements-export-xlsx"
+                  onSelect={() => exportMutation.mutate("xlsx")}
+                >
+                  导出 Excel
+                </DropdownMenuItem>
+              </DropdownMenuContent>
+            </DropdownMenu>
           </div>
         }
       />
@@ -101,6 +147,12 @@ export function ReimbursementsPage() {
         </p>
       ) : null}
 
+      {exportError ? (
+        <p className="rounded-lg border border-red-200 bg-red-50 px-3 py-2 text-sm text-red-600">
+          {exportError}
+        </p>
+      ) : null}
+
       <Card className="space-y-4 p-6">
         <div className="flex flex-col gap-3 md:flex-row md:items-center md:justify-between">
           <Tabs