refactor: API 请求整合与 Bug 修复

前端重构:
- 新增 api/ 目录统一管理所有 API 请求
- 所有 stores 和 pages 改为使用 api 模块
- 修复日期格式化函数，支持 Date 对象和 ISO 字符串
- 修复 TransactionItem 使用 CategoryIcon 组件
- 优化 ChartWrapper 区分 H5 和小程序环境

后端修复:
- 修复 auth 中间件 PUBLIC_PATHS 缺少 demo-login
- 修复备份工具命令注入漏洞，改用 execFile
- 修复 stats 路由 type 参数验证
- 优化分类排序为批量 SQL 更新
- 合并迁移和删除为数据库事务原子操作
- 修复交易和统计日期返回格式
- 新增自动备份功能（启动时备份）

client/src/stores/stats.ts

@@ -1,40 +1,21 @@
 import { defineStore } from 'pinia'
 import { ref } from 'vue'
-import { request } from '@/utils/request'
+import * as api from '@/api/stats'
 import { getCurrentMonth } from '@/utils/format'
 
-export interface Overview {
-  expense: number
-  income: number
-  count: number
-  daily: number
-}
-
-export interface CategoryStat {
-  id: number
-  name: string
-  icon: string
-  color: string
-  amount: number
-  count: number
-}
-
-export interface TrendPoint {
-  date: string
-  amount: number
-}
+// 重新导出类型以保持向后兼容
+export type Overview = api.Overview
+export type CategoryStat = api.CategoryStat
+export type TrendPoint = api.TrendPoint
 
 export const useStatsStore = defineStore('stats', () => {
-  const overview = ref<Overview>({ expense: 0, income: 0, count: 0, daily: 0 })
-  const categoryStats = ref<CategoryStat[]>([])
-  const trendData = ref<TrendPoint[]>([])
+  const overview = ref<api.Overview>({ expense: 0, income: 0, count: 0, daily: 0 })
+  const categoryStats = ref<api.CategoryStat[]>([])
+  const trendData = ref<api.TrendPoint[]>([])
 
   async function fetchOverview(month?: string) {
     try {
-      overview.value = await request<Overview>({
-        url: '/stats/overview',
-        data: { month: month || getCurrentMonth() }
-      })
+      overview.value = await api.getOverview({ month: month || getCurrentMonth() })
     } catch {
       overview.value = { expense: 0, income: 0, count: 0, daily: 0 }
     }
@@ -42,10 +23,7 @@ export const useStatsStore = defineStore('stats', () => {
 
   async function fetchCategoryStats(month?: string, type: string = 'expense') {
     try {
-      categoryStats.value = await request<CategoryStat[]>({
-        url: '/stats/category',
-        data: { month: month || getCurrentMonth(), type }
-      })
+      categoryStats.value = await api.getCategoryStats(month || getCurrentMonth(), type)
     } catch {
       categoryStats.value = []
     }
@@ -53,10 +31,7 @@ export const useStatsStore = defineStore('stats', () => {
 
   async function fetchTrend(month?: string, type: string = 'expense') {
     try {
-      trendData.value = await request<TrendPoint[]>({
-        url: '/stats/trend',
-        data: { month: month || getCurrentMonth(), type }
-      })
+      trendData.value = await api.getTrend(month || getCurrentMonth(), type)
     } catch {
       trendData.value = []
     }