feat: 完善报销单审批流程及退回原因追踪

新增直属领导审批通过接口和审批待办列表查询，报销单退回
支持原因码分类和审批环节标记，优化票据附件去重和路径
回退查找，前端新增退回原因对话框、审批收件箱和工作台
图标组件，补充工具函数和单元测试覆盖。

web/tests/travel-request-detail-leader-approval.test.mjs

@@ -0,0 +1,64 @@
+import assert from 'node:assert/strict'
+import { readFileSync } from 'node:fs'
+import test from 'node:test'
+import { fileURLToPath } from 'node:url'
+
+const detailTemplate = readFileSync(
+  fileURLToPath(new URL('../src/views/TravelRequestDetailView.vue', import.meta.url)),
+  'utf8'
+)
+const detailScript = readFileSync(
+  fileURLToPath(new URL('../src/views/scripts/TravelRequestDetailView.js', import.meta.url)),
+  'utf8'
+)
+const reimbursementService = readFileSync(
+  fileURLToPath(new URL('../src/services/reimbursements.js', import.meta.url)),
+  'utf8'
+)
+
+function extractFunction(source, name) {
+  const signatureIndex = source.indexOf(`function ${name}(`)
+  assert.notEqual(signatureIndex, -1, `${name} should exist`)
+
+  const bodyStart = source.indexOf('{', signatureIndex)
+  assert.notEqual(bodyStart, -1, `${name} should have a body`)
+
+  let depth = 0
+  for (let index = bodyStart; index < source.length; index += 1) {
+    const char = source[index]
+    if (char === '{') {
+      depth += 1
+    } else if (char === '}') {
+      depth -= 1
+      if (depth === 0) {
+        return source.slice(signatureIndex, index + 1)
+      }
+    }
+  }
+
+  assert.fail(`${name} body should be closed`)
+}
+
+test('approval-mode detail collects leader opinion and confirms approval before API call', () => {
+  assert.match(detailScript, /approvalMode:/)
+  assert.match(detailScript, /const leaderOpinion = ref\(''\)/)
+  assert.match(detailScript, /const approveConfirmDialogOpen = ref\(false\)/)
+  assert.match(detailScript, /const canApproveRequest = computed/)
+  assert.match(detailScript, /approveExpenseClaim\(request\.value\.claimId, \{[\s\S]*opinion: leaderOpinion\.value\.trim\(\)/)
+
+  assert.match(detailTemplate, /v-if="showLeaderApprovalPanel"/)
+  assert.match(detailTemplate, /领导意见/)
+  assert.match(detailTemplate, /v-model="leaderOpinion"/)
+  assert.match(detailTemplate, /@click="handleApproveRequest"/)
+  assert.match(detailTemplate, /:open="approveConfirmDialogOpen"/)
+  assert.match(detailTemplate, /confirm-text="确认通过"/)
+  assert.match(detailTemplate, /@confirm="confirmApproveRequest"/)
+
+  const handleApproveRequest = extractFunction(detailScript, 'handleApproveRequest')
+  const confirmApproveRequest = extractFunction(detailScript, 'confirmApproveRequest')
+  assert.doesNotMatch(handleApproveRequest, /approveExpenseClaim/)
+  assert.match(confirmApproveRequest, /approveExpenseClaim/)
+
+  assert.match(reimbursementService, /export function approveExpenseClaim\(claimId, payload = \{\}\)/)
+  assert.match(reimbursementService, /\/approve/)
+})