feat(web): 多 task 串行推进 - task1 完成后自动展示 task2 确认按钮

场景:'出差并且报销招待费'→LLM 拆出 2 个 task→先做完出差申请→
完成后自动展示'继续处理费用报销'按钮→用户确认后推进到报销流程。

- 新增 buildNextTaskSuggestedAction:从 actionPayload.steward_remaining_tasks
  取第一个剩余 task,根据 task_type 生成推进按钮(steward_confirm_flow)
- executeInlineStewardAction 成功后:除'查看单据'外,追加'继续处理下一个 task'按钮
- 用户点击推进按钮复用 handleInlineSuggestedAction 的 steward_confirm_flow 分支
- 前端 28 passed 无回归

web/src/composables/workbenchAiMode/useWorkbenchAiActionRouter.js

@@ -223,8 +223,10 @@ export function useWorkbenchAiActionRouter({
       const result = await executeStewardAction(
         buildStewardActionExecutePayload(action, actionType, contextJson)
       )
+      const resultActions = buildStewardActionResultActions(result)
+      const nextTaskAction = buildNextTaskSuggestedAction(actionPayload)
       finalizeStewardActionMessage(pendingMessage, buildStewardActionResultText(result), {
-        suggestedActions: buildStewardActionResultActions(result)
+        suggestedActions: nextTaskAction ? [...resultActions, nextTaskAction] : resultActions
       })
       return true
     } catch (error) {
@@ -369,6 +371,39 @@ export function useWorkbenchAiActionRouter({
     }]
   }
 
+  function buildNextTaskSuggestedAction(actionPayload = {}) {
+    // 多 task 串行推进:task1 完成后,从剩余 task 列表取下一个,生成推进按钮。
+    // 用户点击推进按钮后,handleInlineSuggestedAction 的 steward_confirm_flow 分支
+    // 会自动拉起下一个 task 的申请预览/报销流程,实现"先做完 A 再做 B"。
+    const remainingTasks = Array.isArray(actionPayload.steward_remaining_tasks)
+      ? actionPayload.steward_remaining_tasks
+      : []
+    const nextTask = remainingTasks[0]
+    if (!nextTask || !nextTask.task_type) {
+      return null
+    }
+    const taskType = String(nextTask.task_type || '').trim()
+    const isApplication = taskType === 'expense_application'
+    const flowId = isApplication ? 'travel_application' : 'travel_reimbursement'
+    const taskLabel = isApplication ? '出差申请' : '费用报销'
+    const ontologyFields = nextTask.ontology_fields || nextTask.ontologyFields || {}
+    return {
+      label: `继续处理${taskLabel}`,
+      description: `接下来处理${taskLabel}: ${String(nextTask.summary || nextTask.title || '').slice(0, 40)}`,
+      icon: isApplication ? 'mdi mdi-file-plus-outline' : 'mdi mdi-receipt-text-plus-outline',
+      action_type: 'steward_continue_next_task',
+      payload: {
+        steward_confirm_flow: true,
+        flow_id: flowId,
+        steward_current_task: nextTask,
+        expense_type: String(ontologyFields.expense_type || 'travel').trim() || 'travel',
+        expense_type_label: String(ontologyFields.expense_type_label || '差旅费').trim() || '差旅费',
+        ontology_fields: ontologyFields,
+        original_message: String(nextTask.summary || nextTask.title || `继续处理${taskLabel}`).trim()
+      }
+    }
+  }
+
   return {
     handleInlineSuggestedAction
   }