feat: v1.2 数据可视化与统计增强

新增功能：
- uCharts 集成，支持环形图和折线图
- 统计页分类占比环形图
- 统计页每日趋势折线图
- 统计页增加最大单笔和对比上月指标
- 首页今日支出卡片

组件：
- ChartWrapper 通用图表组件（支持 pie/line/column）
- 支持 H5 和微信小程序双端

依赖：
- 新增 @qiun/ucharts 图表库

client/src/components/ChartWrapper/ChartWrapper.vue

@@ -0,0 +1,93 @@
+<template>
+  <view class="chart-wrap">
+    <canvas
+      :canvas-id="canvasId"
+      :id="canvasId"
+      class="chart-canvas"
+      :style="{ width: width + 'rpx', height: height + 'rpx' }"
+      @tap="onTap"
+    ></canvas>
+  </view>
+</template>
+
+<script setup lang="ts">
+import { ref, onMounted, watch, nextTick } from 'vue'
+// @ts-ignore
+import uCharts from '@qiun/ucharts/u-charts.min.js'
+
+const props = defineProps<{
+  canvasId: string
+  type: 'pie' | 'line' | 'column'
+  chartData: any
+  width?: number
+  height?: number
+}>()
+
+const emit = defineEmits(['tap'])
+
+let chartInstance: any = null
+
+function drawChart() {
+  if (!props.chartData) return
+
+  const query = uni.createSelectorQuery().in(getCurrentInstance()?.proxy)
+  query.select(`#${props.canvasId}`)
+    .fields({ node: true, size: true })
+    .exec((res) => {
+      if (!res[0]) return
+
+      const canvas = res[0].node
+      const ctx = canvas.getContext('2d')
+
+      const dpr = uni.getSystemInfoSync().pixelRatio
+      canvas.width = res[0].width * dpr
+      canvas.height = res[0].height * dpr
+      ctx.scale(dpr, dpr)
+
+      const config: any = {
+        context: ctx,
+        canvas2d: true,
+        pixelRatio: dpr,
+        width: res[0].width,
+        height: res[0].height,
+        animation: true,
+        background: '#FFFFFF',
+        padding: [15, 15, 15, 15],
+        ...props.chartData
+      }
+
+      chartInstance = new uCharts(config)
+    })
+}
+
+import { getCurrentInstance } from 'vue'
+
+function onTap(e: any) {
+  chartInstance?.touchLegend(e)
+  emit('tap', e)
+}
+
+onMounted(() => {
+  nextTick(() => {
+    setTimeout(drawChart, 100)
+  })
+})
+
+watch(() => props.chartData, () => {
+  nextTick(() => {
+    setTimeout(drawChart, 100)
+  })
+}, { deep: true })
+</script>
+
+<style lang="scss" scoped>
+.chart-wrap {
+  width: 100%;
+  display: flex;
+  justify-content: center;
+}
+
+.chart-canvas {
+  display: block;
+}
+</style>