fix: add defensive checks to BudgetChartAnalysis chart data

- Added null checks for overallStats.month/year in gauge charts
- Added null checks for burndown and year burndown charts
- Fixed BaseChart.vue template using undefined 'chartData' variable
- Changed :data="chartData" to :data="data" to use prop directly

Fixes console errors when viewing /budget-v2 page
Verified: 0 errors, only 1 harmless plugin warning

Refs: openspec/changes/migrate-remaining-echarts-to-chartjs

Web/src/components/Budget/BudgetChartAnalysis.vue

@@ -261,6 +261,19 @@ const formatMoney = (val) => {
 
 // 月度仪表盘数据
 const monthGaugeData = computed(() => {
+  // 防御性检查：如果数据未加载，返回默认结构
+  if (!props.overallStats || !props.overallStats.month) {
+    return {
+      datasets: [{
+        data: [0, 100],
+        backgroundColor: [getCssVar('--chart-axis'), getCssVar('--chart-axis')],
+        borderWidth: 0,
+        circumference: 180,
+        rotation: 270
+      }]
+    }
+  }
+
   const rate = parseFloat(props.overallStats.month.rate || 0)
   const isExpense = props.activeTab === BudgetCategory.Expense
 
@@ -329,6 +342,19 @@ const monthGaugeOptions = computed(() => {
 
 // 年度仪表盘数据
 const yearGaugeData = computed(() => {
+  // 防御性检查：如果数据未加载，返回默认结构
+  if (!props.overallStats || !props.overallStats.year) {
+    return {
+      datasets: [{
+        data: [0, 100],
+        backgroundColor: [getCssVar('--chart-axis'), getCssVar('--chart-axis')],
+        borderWidth: 0,
+        circumference: 180,
+        rotation: 270
+      }]
+    }
+  }
+
   const rate = parseFloat(props.overallStats.year.rate || 0)
   const isExpense = props.activeTab === BudgetCategory.Expense
 
@@ -493,6 +519,14 @@ const varianceChartOptions = computed(() => {
 
 // 月度燃尽图数据
 const burndownChartData = computed(() => {
+  // 防御性检查
+  if (!props.overallStats || !props.overallStats.month || !props.selectedDate) {
+    return {
+      labels: [],
+      datasets: []
+    }
+  }
+
   const refDate = props.selectedDate
   const year = refDate.getFullYear()
   const month = refDate.getMonth()
@@ -623,6 +657,14 @@ const burndownChartOptions = computed(() => {
 
 // 年度燃尽图数据
 const yearBurndownChartData = computed(() => {
+  // 防御性检查
+  if (!props.overallStats || !props.overallStats.year || !props.selectedDate) {
+    return {
+      labels: [],
+      datasets: []
+    }
+  }
+
   const refDate = props.selectedDate
   const year = refDate.getFullYear()
 

Web/src/components/Charts/BaseChart.vue

@@ -5,7 +5,7 @@
     <component
       v-else
       :is="chartComponent"
-      :data="chartData"
+      :data="data"
       :options="mergedOptions"
       :plugins="chartPlugins"
       @chart:render="onChartRender"