fix: 优化文档16项问题修复

- 问题1/3: 绩效考核/培训记录员工姓名可点击跳转员工详情页
- 问题2: 离职证明模板支持自定义+员工端下载
- 问题4(P0): 修复工资填写后数据归零问题
- 问题5: 社保添加员工参保信息列表
- 问题6(P0): 商业保险支持为员工参保
- 问题7(P0): 员工福利支持为员工添加福利
- 问题8: 规章制度支持导入Word文档
- 问题9: 文本模板下载Word增加HTML格式
- 问题10: 模板下载变量替换修复(排除token参数)
- 问题11(P0): 电子签署发起时员工下拉框有选项
- 问题12: 新增绩效记录添加考评人选项
- 问题13: 违纪记录添加处罚执行细节
- 问题14: 特殊员工列表添加查看详情按钮和姓名链接
- 问题15: 员工福利汇总正确显示参保人员
- 问题16(P0): 证据链验证修复(递归排序key+自动修复历史哈希)

frontend/src/pages/portal/ResignationApply.tsx

@@ -4,7 +4,7 @@
 import { useState, useRef } from 'react'
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
 import { toast } from 'sonner'
-import { UserX, Clock, FileText, Camera, X, Image as ImageIcon } from 'lucide-react'
+import { UserX, Clock, FileText, Camera, X, Image as ImageIcon, Download } from 'lucide-react'
 import { portalApi } from '../../lib/api-services'
 import Card from '../../components/ui/Card'
 import Button from '../../components/ui/Button'
@@ -205,6 +205,7 @@ export default function ResignationApply() {
             {records.map((r: any) => {
               const statusCfg = STATUS_MAP[r.status] || STATUS_MAP.DRAFT
               const canWithdraw = r.status === 'DRAFT' || r.status === 'PENDING_APPROVAL'
+              const canDownload = r.status === 'COMPLETED'
               return (
                 <div key={r.id} className="p-3 rounded-lg border border-gray-100">
                   <div className="flex items-center justify-between mb-2">
@@ -223,6 +224,29 @@ export default function ResignationApply() {
                       <div className="text-xs text-gray-500 mt-1">{r.remark}</div>
                     )}
                   </div>
+                  {canDownload && (
+                    <div className="mt-2 pt-2 border-t border-gray-50">
+                      <Button
+                        variant="secondary"
+                        size="sm"
+                        onClick={async () => {
+                          try {
+                            const blob = await portalApi.downloadCertificate(r.id)
+                            const url = URL.createObjectURL(blob)
+                            const a = document.createElement('a')
+                            a.href = url
+                            a.download = `离职证明.doc`
+                            a.click()
+                            URL.revokeObjectURL(url)
+                          } catch {
+                            toast.error('下载失败')
+                          }
+                        }}
+                      >
+                        <Download className="w-4 h-4 mr-1" />下载离职证明
+                      </Button>
+                    </div>
+                  )}
                   {canWithdraw && (
                     <div className="mt-2 pt-2 border-t border-gray-50">
                       <Button