feat: 增加差旅报销标准测算和财务终审流程

新增差旅报销测算接口及 Spreadsheet 规则解析，审批流程拆分
直属领导审批与财务终审两阶段并细分权限，修复 PDF 文本层
缺失时自动回退 OCR，提交后清理关联会话，前端适配审批流
交互并补充单元测试。

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

@@ -172,6 +172,13 @@ test('expense item upload remains limited to one receipt per detail row', () =>
   assert.match(detailViewScript, /fileCount > 1[\s\S]*一条费用明细只能上传一张单据/)
 })
 
+test('expense item upload patches OCR amount into the visible detail row', () => {
+  assert.match(detailViewScript, /const recognizedItemAmount = Number\(payload\?\.item_amount \?\? payload\?\.itemAmount\)/)
+  assert.match(detailViewScript, /itemPatch\.itemAmount = recognizedItemAmount/)
+  assert.match(detailViewScript, /itemPatch\.amount = formatCurrency\(recognizedItemAmount\)/)
+  assert.match(detailViewScript, /expenseEditor\.itemAmount = String\(recognizedItemAmount\)/)
+})
+
 test('return reason dialog is wired into approval and detail return actions', () => {
   assert.match(returnReasonDialog, /missing_attachment/)
   assert.match(returnReasonDialog, /invoice_mismatch/)