feat(web): AI 工作台文件预览/附件关联任务与草稿分支

- 新增 WorkbenchAiFilePreviewDialog 附件预览对话框及 useWorkbenchAiFilePreview，附件支持点击预览
- 新增 attachmentAssociationJobs/linkedReimbursementDraftJobs 前端服务与对应 composable，接入后台任务轮询与状态展示
- 新增 travelReimbursementDraftBranchModel 草稿分支模型，报销关联门控支持跳过/选择草稿
- PersonalWorkbenchAiMode 及各 composable（expense/document/steward/application-preview/attachment-association）重构适配，WorkbenchAiComposer/FileStrip 样式与交互完善
- DocumentsCenter/ReceiptFolder/TravelReimbursementCreate 等视图及 scripts 重构，风险/差旅规划/审批等工具适配
- 新增/更新前端测试：application-result-card、reimbursement-list-preview-fetch、guided-flow、composer-components 等

web/tests/travel-request-detail-risk-advice.test.mjs

@@ -434,6 +434,13 @@ test('AI advice ignores approval opinions and flow logs as risks', () => {
         severity: 'info',
         label: '财务审核通过',
         message: '周晓彤 已完成财务审核，进入归档入账。'
+      },
+      {
+        source: 'application_link_sync',
+        event_type: 'expense_application_reimbursement_deleted',
+        severity: 'warning',
+        label: '关联报销单已删除',
+        message: '关联报销单 RDELETE01 已删除，申请单已回到待关联状态。'
       }
     ]
   })