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/src/services/attachmentAssociationJobs.js

@@ -0,0 +1,21 @@
+import { apiRequest } from './api.js'
+
+function normalizeJobId(jobId) {
+  return String(jobId || '').trim()
+}
+
+export function createAttachmentAssociationJob(payload = {}) {
+  return apiRequest('/reimbursements/attachment-association-jobs', {
+    method: 'POST',
+    body: JSON.stringify(payload || {})
+  })
+}
+
+export function fetchAttachmentAssociationJob(jobId) {
+  const normalizedJobId = normalizeJobId(jobId)
+  if (!normalizedJobId) {
+    throw new Error('附件关联任务不存在或已失效。')
+  }
+  return apiRequest(`/reimbursements/attachment-association-jobs/${encodeURIComponent(normalizedJobId)}`)
+}
+

web/src/services/linkedReimbursementDraftJobs.js

@@ -0,0 +1,13 @@
+import { apiRequest } from './api.js'
+
+export function createLinkedReimbursementDraftJob(payload = {}) {
+  return apiRequest('/reimbursements/linked-reimbursement-draft-jobs', {
+    method: 'POST',
+    body: JSON.stringify(payload)
+  })
+}
+
+export function fetchLinkedReimbursementDraftJob(jobId) {
+  const normalizedJobId = encodeURIComponent(String(jobId || '').trim())
+  return apiRequest(`/reimbursements/linked-reimbursement-draft-jobs/${normalizedJobId}`)
+}