refactor: split project into web and server directories

- Move frontend to web/ directory
- Add server/ directory for backend
- Restructure project for前后端分离架构

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/src/composables/useRequests.js

@@ -0,0 +1,60 @@
+import { computed, reactive, ref } from 'vue'
+import { initialRequests } from '../data/requests.js'
+
+export function useRequests() {
+  const requests = ref(initialRequests)
+  const entityMap = {
+    'Northstar China Ltd.': 'Northstar China Ltd.',
+    'Northstar Singapore Pte.': 'Northstar Singapore Pte.',
+    'Northstar US Inc.': 'Northstar US Inc.'
+  }
+  const search = ref('')
+  const filters = reactive({ entity: '全部主体', category: '全部费用', risk: '全部风险' })
+  const ranges = ['今日', '本周', '本月']
+  const activeRange = ref('本周')
+
+  const filteredRequests = computed(() => {
+    const key = search.value.trim().toLowerCase()
+    return requests.value.filter((item) => {
+      const matchesSearch = !key || `${item.id}${item.person}${item.category}${item.risk}`.toLowerCase().includes(key)
+      const matchesEntity = filters.entity === '全部主体' || item.entity === entityMap[filters.entity]
+      const matchesCategory = filters.category === '全部费用' || item.category === filters.category
+      const matchesRisk = filters.risk === '全部风险'
+        || (filters.risk === '高风险' && item.status === 'danger')
+        || (filters.risk === '需解释' && item.status === 'warning')
+        || (filters.risk === '低风险' && item.status === 'success')
+  const matchesRange = activeRange.value === 'custom'
+    || activeRange.value === '本月'
+    || (activeRange.value === '本周' && item.range !== '本月')
+    || (activeRange.value === '今日' && item.range === '今日')
+      return matchesSearch && matchesEntity && matchesCategory && matchesRisk && matchesRange
+    })
+  })
+
+  function updateRequest(requestId, updates) {
+    requests.value = requests.value.map((item) => (item.id === requestId ? { ...item, ...updates } : item))
+  }
+
+  function approveRequest(request) {
+    updateRequest(request.id, {
+      verdict: '已通过',
+      status: 'success',
+      risk: '已完成人工确认'
+    })
+    return `${request.id} 已标记为通过，审计日志已更新。`
+  }
+
+  function rejectRequest(request) {
+    updateRequest(request.id, {
+      verdict: '已退回补件',
+      status: 'danger',
+      risk: '待申请人补充差旅行程与票据'
+    })
+    return `${request.id} 已退回，系统将通知申请人补充材料。`
+  }
+
+  return {
+    requests, search, filters, ranges, activeRange,
+    filteredRequests, approveRequest, rejectRequest
+  }
+}