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/src/utils/approvalInbox.js

@@ -1,5 +1,9 @@
 import { mapExpenseClaimToRequest } from '../composables/useRequests.js'
-import { canManageExpenseClaims } from './accessControl.js'
+import {
+  canApproveLeaderExpenseClaims,
+  canManageExpenseClaims,
+  isFinanceUser
+} from './accessControl.js'
 
 export function canProcessApprovalRequest(request, currentUser) {
   const node = String(request?.workflowNode || '').trim()
@@ -14,12 +18,18 @@ export function canProcessApprovalRequest(request, currentUser) {
     return true
   }
 
-  return (
+  if (isFinanceUser(currentUser) && node.includes('财务')) {
+    return true
+  }
+
+  const isLeaderApprovalNode = (
     node.includes('直属领导')
     || node.includes('领导审批')
     || node.includes('部门负责人')
     || node.includes('负责人审批')
   )
+
+  return canApproveLeaderExpenseClaims(currentUser) && isLeaderApprovalNode
 }
 
 export function listPendingApprovalRequests(claimsPayload, currentUser) {