fix: 修复统计图表不显示与对比上月Infinity问题

- ChartWrapper: 添加 type 属性修复 uCharts 不渲染
- ChartWrapper: 使用 pixelRatio=1 避免双重缩放导致字体线条过大
- ChartWrapper: 统一 fontSize/fontColor/padding 配置
- ChartWrapper: 挂载时保存实例引用避免异步回调中 getCurrentInstance 返回 undefined
- stats: Number() 强制类型转换避免字符串导致 Infinity
- stats: !prev 宽松判断覆盖 null/undefined/0 除零情况
- stores: fetchOverview/fetchCategoryStats/fetchTrend 确保数据字段为数字

client/src/pages/stats/index.vue

@@ -57,7 +57,7 @@
         canvasId="categoryChart"
         type="pie"
         :chartData="categoryChartData"
-        :width="600"
+        :width="650"
         :height="400"
       />
       <view class="chart-legend">
@@ -90,7 +90,7 @@
         canvasId="trendChart"
         type="line"
         :chartData="trendChartData"
-        :width="600"
+        :width="650"
         :height="400"
       />
       <view class="trend-list">
@@ -149,9 +149,9 @@ const categoryChartData = computed(() => {
     series: [{
       data: categoryStats.value.map(item => ({
         name: item.name,
-        value: item.amount / 100,
-        color: item.color
-      }))
+        value: item.amount / 100
+      })),
+      color: categoryStats.value.map(item => item.color)
     }],
     extra: {
       pie: {
@@ -174,9 +174,9 @@ const trendChartData = computed(() => {
     categories: trendData.value.map(p => p.date.slice(8) + '日'),
     series: [{
       name: tabType.value === 'expense' ? '支出' : '收入',
-      data: trendData.value.map(p => p.amount / 100),
-      color: '#FF8C69'
+      data: trendData.value.map(p => p.amount / 100)
     }],
+    color: ['#FF8C69'],
     extra: {
       line: {
         type: 'curve',
@@ -187,6 +187,15 @@ const trendChartData = computed(() => {
         opacity: 0.2,
         gradient: true
       }
+    },
+    xAxis: {
+      disableGrid: true,
+      rotateLabel: true,
+      rotateAngle: -45
+    },
+    yAxis: {
+      gridColor: '#F0E0D6',
+      data: [{ min: 0 }]
     }
   }
 })
@@ -204,7 +213,8 @@ const monthCompareText = computed(() => {
   if (!prevMonthData.value) return ''
   const current = tabType.value === 'expense' ? overview.value.expense : overview.value.income
   const prev = tabType.value === 'expense' ? prevMonthData.value.expense : prevMonthData.value.income
-  if (prev === 0) return '无上月数据'
+  // 处理 prev 为 0、null、undefined 的情况，避免除零产生 Infinity
+  if (!prev) return '无上月数据'
   const pct = Math.round(((current - prev) / prev) * 100)
   if (pct > 0) return `+${pct}%`
   if (pct < 0) return `${pct}%`
@@ -275,7 +285,13 @@ async function fetchPrevMonthData() {
     const [y, m] = currentMonth.value.split('-').map(Number)
     const prevMonth = m === 1 ? `${y - 1}-12` : `${y}-${String(m - 1).padStart(2, '0')}`
     const data = await getOverview({ month: prevMonth })
-    prevMonthData.value = data
+    // 确保数据字段是数字类型，避免 null/undefined 导致 Infinity
+    prevMonthData.value = {
+      expense: Number(data?.expense) || 0,
+      income: Number(data?.income) || 0,
+      count: Number(data?.count) || 0,
+      daily: Number(data?.daily) || 0
+    }
   } catch {
     prevMonthData.value = null
   }