feat(web): AI 工作台多 task 串行推进与会话适配

- useWorkbenchAiApplicationPreviewFlow/useWorkbenchAiActionRouter/useWorkbenchAiCommandIntents 支持 task1 完成后自动推进 task2，确认按钮直接拉起申请预览，草稿/提交成功后继续推进下一 task
- workbenchAiIntentPlannerModel/workbenchAiMessageModel/workbenchAiCommandIntentModel 适配多 task 意图规划与消息结构
- aiApplicationPreviewActions/aiApplicationPrecheckModel/aiExpenseDraftModel/aiWorkbenchConversationStore 草稿与会话存储适配
- PersonalWorkbenchAiMode 与样式适配，更新 preview-actions/expense-draft/conversation-store/fast-preview/action-router/command-intent/intent-planner 测试

web/tests/ai-workbench-conversation-store.test.mjs

@@ -67,3 +67,37 @@ test('AI workbench conversation store persists scoped history for sidebar sessio
   assert.equal(nextHistory.length, 1)
   assert.equal(nextHistory[0].id, 'conv-first')
 })
+
+test('AI workbench conversation store preserves stewardRemainingTasks on messages', () => {
+  installLocalStorageMock()
+  const user = { username: 'caoxiaozhu' }
+  const remainingTasks = [
+    { task_id: 't2', task_type: 'reimbursement', ontology_fields: { expense_type: 'meal' } }
+  ]
+
+  saveAiWorkbenchConversation(user, {
+    id: 'conv-multi-task',
+    title: '出差+招待费',
+    updatedAt: Date.now(),
+    messages: [
+      { id: 'u1', role: 'user', content: '出差+报销招待费' },
+      {
+        id: 'a1',
+        role: 'assistant',
+        content: '申请草稿已保存',
+        stewardRemainingTasks: remainingTasks
+      }
+    ]
+  })
+
+  const history = loadAiWorkbenchConversationHistory(user)
+  assert.equal(history.length, 1)
+  // 历史摘要不要求保留 stewardRemainingTasks,但加载完整会话时消息上应保留。
+  // 这里通过 saveAiWorkbenchConversation 的往返确认 normalizeMessage 不会丢弃该字段。
+  const stored = JSON.parse(globalThis.window.localStorage.getItem(
+    'x-financial:workbench-ai-conversations:caoxiaozhu'
+  ))
+  const conversation = stored.find((item) => item.id === 'conv-multi-task')
+  const persistedMessage = conversation.messages.find((m) => m.id === 'a1')
+  assert.deepEqual(persistedMessage.stewardRemainingTasks, remainingTasks)
+})