feat(client): 行政代提交/代上传 owner 选择入口(F33)

- 报销创建支持选择 ownerEmployeeId（delegation-grants received）
- 票据上传支持 owner_employee_id（delegation-grants received）
- 保持普通员工流程不变，权限不足由后端阻断

client/src/pages/ReimbursementsPage.tsx

@@ -1,7 +1,9 @@
+import { useState } from "react";
 import { Link, useSearchParams } from "react-router-dom";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { isApiError } from "../api/types";
 import { mapApiErrorMessage } from "../api/errorMessages";
+import { fetchMyDelegations } from "../api/delegations";
 import { createReimbursement, fetchReimbursements, type ReimbursementStatus } from "../api/reimbursements";
 import { useAuth } from "../auth/AuthContext";
 import { hasPermission } from "../auth/permissions";
@@ -15,21 +17,35 @@ const PAGE_SIZE = 20;
 
 export function ReimbursementsPage() {
   const [searchParams, setSearchParams] = useSearchParams();
-  const { permissions } = useAuth();
+  const { permissions, me } = useAuth();
   const queryClient = useQueryClient();
 
   const status = (searchParams.get("status") as ReimbursementStatus | null) ?? "draft";
   const page = Number(searchParams.get("page") ?? "1") || 1;
   const scope = (searchParams.get("scope") as "own" | "all" | null) ?? "own";
   const canViewAll = hasPermission(permissions, "expense.view_all");
+  const canProxySubmit = hasPermission(permissions, "expense.proxy_submit");
+  const isAdministration = (me?.roleCodes ?? []).includes("administration");
+  const showProxyOwnerSelector = canProxySubmit && isAdministration;
+
+  const [proxyOwnerEmployeeId, setProxyOwnerEmployeeId] = useState("");
 
   const listQuery = useQuery({
     queryKey: ["reimbursements", "list", status, page, scope],
     queryFn: () => fetchReimbursements({ status, page, pageSize: PAGE_SIZE, scope }),
   });
 
+  const proxyDelegationsQuery = useQuery({
+    enabled: showProxyOwnerSelector,
+    queryKey: ["delegations", "mine", "active"],
+    queryFn: () => fetchMyDelegations("active"),
+  });
+
   const createMutation = useMutation({
-    mutationFn: () => createReimbursement({}),
+    mutationFn: () =>
+      createReimbursement({
+        ownerEmployeeId: proxyOwnerEmployeeId || undefined,
+      }),
     onSuccess: async () => {
       await queryClient.invalidateQueries({ queryKey: ["reimbursements"] });
     },
@@ -43,14 +59,34 @@ export function ReimbursementsPage() {
         title="我的报销"
         subtitle="报销列表、详情与提交/撤回/支付动作入口。"
         actions={
-          <Button
-            data-testid="reimbursements-create"
-            disabled={createMutation.isPending}
-            onClick={() => createMutation.mutate()}
-            type="button"
-          >
-            {createMutation.isPending ? "创建中..." : "新建报销"}
-          </Button>
+          <div className="flex flex-col gap-2 sm:flex-row sm:items-center">
+            {showProxyOwnerSelector ? (
+              <select
+                className="h-11 rounded-lg border border-slate-300 bg-white px-3 py-2 text-sm"
+                data-testid="reimbursements-owner-select"
+                onChange={(event) => setProxyOwnerEmployeeId(event.target.value)}
+                value={proxyOwnerEmployeeId}
+              >
+                <option value="">自己</option>
+                {(proxyDelegationsQuery.data?.received ?? [])
+                  .filter((item) => item.status === "active")
+                  .map((item) => (
+                    <option key={item.id} value={item.principalEmployeeId}>
+                      {item.principal?.name ?? item.principalEmployeeId}
+                    </option>
+                  ))}
+              </select>
+            ) : null}
+
+            <Button
+              data-testid="reimbursements-create"
+              disabled={createMutation.isPending}
+              onClick={() => createMutation.mutate()}
+              type="button"
+            >
+              {createMutation.isPending ? "创建中..." : "新建报销"}
+            </Button>
+          </div>
         }
       />