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-leader-approval.test.mjs

@@ -44,14 +44,24 @@ test('approval-mode detail collects leader opinion and confirms approval before
   assert.match(detailScript, /const leaderOpinion = ref\(''\)/)
   assert.match(detailScript, /const approveConfirmDialogOpen = ref\(false\)/)
   assert.match(detailScript, /const canApproveRequest = computed/)
+  assert.match(detailScript, /canApproveLeaderExpenseClaims/)
+  assert.match(detailScript, /isFinanceApprovalStage/)
+  assert.match(detailScript, /approvalOpinionTitle/)
+  assert.match(detailScript, /approvalConfirmDescription/)
+  assert.match(detailScript, /approvalNextStage/)
   assert.match(detailScript, /approveExpenseClaim\(request\.value\.claimId, \{[\s\S]*opinion: leaderOpinion\.value\.trim\(\)/)
+  assert.match(detailScript, /toast\(approvalSuccessToast\.value\)/)
 
   assert.match(detailTemplate, /v-if="showLeaderApprovalPanel"/)
-  assert.match(detailTemplate, /领导意见/)
+  assert.match(detailTemplate, /\{\{ approvalOpinionTitle \}\}/)
   assert.match(detailTemplate, /v-model="leaderOpinion"/)
+  assert.match(detailTemplate, /:placeholder="approvalOpinionPlaceholder"/)
   assert.match(detailTemplate, /@click="handleApproveRequest"/)
   assert.match(detailTemplate, /:open="approveConfirmDialogOpen"/)
+  assert.match(detailTemplate, /:badge="approvalConfirmBadge"/)
+  assert.match(detailTemplate, /:description="approvalConfirmDescription"/)
   assert.match(detailTemplate, /confirm-text="确认通过"/)
+  assert.match(detailTemplate, /\{\{ approvalNextStage \}\}/)
   assert.match(detailTemplate, /@confirm="confirmApproveRequest"/)
 
   const handleApproveRequest = extractFunction(detailScript, 'handleApproveRequest')