feat: 增强差旅报销审核流程与票据智能推理

优化本体解析和编排器的差旅场景处理能力，完善报销单草稿
保存和费用明细同步逻辑，前端报销创建页面增加行程推理和
票据审核交互，新增助手会话快照工具函数，补充单元测试。

web/tests/reimbursementTextInference.test.mjs

@@ -5,6 +5,8 @@ import {
   buildLocalExtractionProgressMessages,
   buildLocalIntentPreview,
   inferLocalFlowCandidates,
+  shouldRequestExpenseIntentConfirmation,
+  shouldRequestExpenseSceneSelection,
   summarizeSemanticIntentDetail
 } from '../src/utils/reimbursementTextInference.js'
 
@@ -40,3 +42,32 @@ test('semantic intent detail includes recognized expense type', () => {
     '已识别为报销场景，当前目标是草稿生成，费用类型为交通费'
   )
 })
+
+test('ambiguous expense prompt waits for scene selection before extraction preview', () => {
+  const ambiguousMessage = '业务发生时间:2026-02-20 至 2026-02-23，去上海支持上海电力部署项目，申请报销'
+
+  assert.equal(shouldRequestExpenseSceneSelection(ambiguousMessage), true)
+  assert.match(buildLocalIntentPreview(ambiguousMessage), /需要先由用户选择场景/)
+  assert.doesNotMatch(buildLocalIntentPreview(ambiguousMessage), /草稿生成/)
+})
+
+test('clear expense type does not request scene selection', () => {
+  const travelMessage = '业务发生时间:2026-02-20 至 2026-02-23，去上海出差支持上海电力部署项目，申请差旅报销'
+
+  assert.equal(shouldRequestExpenseSceneSelection(travelMessage), false)
+  assert.match(buildLocalIntentPreview(travelMessage), /差旅费/)
+})
+
+test('business activity without expense intent asks for reimbursement confirmation first', () => {
+  const businessMessage = '去上海电力支撑项目部署'
+
+  assert.equal(shouldRequestExpenseIntentConfirmation(businessMessage), true)
+  assert.match(buildLocalIntentPreview(businessMessage), /是否发起报销尚不明确/)
+  assert.equal(shouldRequestExpenseSceneSelection(businessMessage), false)
+})
+
+test('explicit technical operation does not ask for reimbursement confirmation', () => {
+  const operationMessage = '去上海电力支撑项目部署，帮我整理服务器部署步骤'
+
+  assert.equal(shouldRequestExpenseIntentConfirmation(operationMessage), false)
+})