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/requestProgressSteps.test.mjs

@@ -0,0 +1,90 @@
+import assert from 'node:assert/strict'
+import test from 'node:test'
+
+import { mapExpenseClaimToRequest } from '../src/composables/useRequests.js'
+
+test('progress steps show approval operator time and current stay duration', () => {
+  const originalNow = Date.now
+  Date.now = () => new Date('2026-05-20T05:00:00.000Z').getTime()
+
+  try {
+    const request = mapExpenseClaimToRequest({
+      id: 'claim-1',
+      claim_no: 'EXP-202605-001',
+      employee_name: '张三',
+      department_name: '市场部',
+      expense_type: 'transport',
+      reason: '交通报销',
+      location: '上海',
+      amount: 88,
+      invoice_count: 1,
+      occurred_at: '2026-05-20T01:00:00.000Z',
+      submitted_at: '2026-05-20T02:00:00.000Z',
+      created_at: '2026-05-20T01:30:00.000Z',
+      updated_at: '2026-05-20T03:30:00.000Z',
+      status: 'submitted',
+      approval_stage: '财务审批',
+      risk_flags_json: [
+        {
+          source: 'manual_approval',
+          operator: '李经理',
+          previous_approval_stage: '直属领导审批',
+          next_approval_stage: '财务审批',
+          created_at: '2026-05-20T03:30:00.000Z'
+        }
+      ],
+      items: []
+    })
+
+    const leaderStep = request.progressSteps.find((step) => step.label === '直属领导审批')
+    const financeStep = request.progressSteps.find((step) => step.label === '财务审批')
+    const aiStep = request.progressSteps.find((step) => step.label === 'AI预审')
+
+    assert.equal(leaderStep.time, '李经理通过')
+    assert.match(leaderStep.detail, /2026-05-20/)
+    assert.match(leaderStep.title, /李经理审批通过/)
+    assert.equal(aiStep.time, 'AI预审通过')
+    assert.match(aiStep.detail, /2026-05-20/)
+    assert.equal(financeStep.current, true)
+    assert.equal(financeStep.time, '停留 1小时30分钟')
+  } finally {
+    Date.now = originalNow
+  }
+})
+
+test('current direct manager step shows how long the claim has stayed there', () => {
+  const originalNow = Date.now
+  Date.now = () => new Date('2026-05-20T05:15:00.000Z').getTime()
+
+  try {
+    const request = mapExpenseClaimToRequest({
+      id: 'claim-2',
+      claim_no: 'EXP-202605-002',
+      employee_name: '王五',
+      department_name: '市场部',
+      expense_type: 'office',
+      reason: '办公用品',
+      location: '上海',
+      amount: 128,
+      invoice_count: 1,
+      occurred_at: '2026-05-20T01:00:00.000Z',
+      submitted_at: '2026-05-20T02:00:00.000Z',
+      created_at: '2026-05-20T01:30:00.000Z',
+      updated_at: '2026-05-20T02:00:00.000Z',
+      status: 'submitted',
+      approval_stage: '直属领导审批',
+      risk_flags_json: [],
+      items: []
+    })
+
+    const leaderStep = request.progressSteps.find((step) => step.label === '直属领导审批')
+    const submitStep = request.progressSteps.find((step) => step.label === '待提交')
+
+    assert.equal(submitStep.time, '王五提交')
+    assert.match(submitStep.detail, /2026-05-20/)
+    assert.equal(leaderStep.current, true)
+    assert.equal(leaderStep.time, '停留 3小时15分钟')
+  } finally {
+    Date.now = originalNow
+  }
+})