chore: migrate remaining ECharts components to Chart.js

- Migrated 4 components from ECharts to Chart.js:
  * MonthlyExpenseCard.vue (折线图)
  * DailyTrendChart.vue (双系列折线图)
  * ExpenseCategoryCard.vue (环形图)
  * BudgetChartAnalysis.vue (仪表盘 + 多种图表)

- Removed all ECharts imports and environment variable switches
- Unified all charts to use BaseChart.vue component
- Build verified: pnpm build success ✓
- No echarts imports remaining ✓

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

Web/src/components/IconSelector.vue

@@ -0,0 +1,202 @@
+<template>
+  <PopupContainer
+    :show="show"
+    :title="title"
+    show-cancel-button
+    show-confirm-button
+    confirm-text="选择"
+    cancel-text="取消"
+    @update:show="emit('update:show', $event)"
+    @confirm="handleConfirm"
+    @cancel="handleCancel"
+  >
+    <div class="icon-selector">
+      <!-- 搜索框 -->
+      <van-search
+        v-model="searchKeyword"
+        placeholder="搜索图标"
+        :clearable="true"
+        @input="handleSearch"
+      />
+
+      <!-- 图标列表 -->
+      <div class="icon-list" v-if="filteredIcons.length > 0">
+        <div
+          v-for="icon in paginatedIcons"
+          :key="icon.iconIdentifier"
+          class="icon-item"
+          :class="{ active: selectedIconIdentifier === icon.iconIdentifier }"
+          @click="handleSelectIcon(icon)"
+        >
+          <Icon
+            :icon-identifier="icon.iconIdentifier"
+            :size="32"
+            :color="selectedIconIdentifier === icon.iconIdentifier ? '#1989fa' : '#969799'"
+          />
+          <span class="icon-label">{{ icon.iconName }}</span>
+        </div>
+      </div>
+
+      <!-- 无结果提示 -->
+      <van-empty v-else description="未找到匹配的图标" />
+
+      <!-- 分页 -->
+      <van-pagination
+        v-if="totalPages > 1"
+        v-model:currentPage="currentPage"
+        :total-items="filteredIcons.length"
+        :items-per-page="pageSize"
+        @change="handlePageChange"
+        class="pagination"
+      />
+    </div>
+  </PopupContainer>
+</template>
+
+<script setup lang="ts">
+import { ref, computed, watch } from 'vue'
+import { showToast } from 'vant'
+import Icon from './Icon.vue'
+import PopupContainer from './PopupContainer.vue'
+
+interface Icon {
+  iconIdentifier: string
+  iconName: string
+  collectionName: string
+}
+
+interface Props {
+  show: boolean
+  icons: Icon[]
+  title?: string
+  defaultIconIdentifier?: string
+}
+
+const props = withDefaults(defineProps<Props>(), {
+  title: '选择图标',
+  defaultIconIdentifier: ''
+})
+
+const emit = defineEmits<{
+  'update:show': [value: boolean]
+  confirm: [iconIdentifier: string]
+  cancel: []
+}>()
+
+const searchKeyword = ref('')
+const currentPage = ref(1)
+const pageSize = ref(20)
+const selectedIconIdentifier = ref(props.defaultIconIdentifier)
+
+// 搜索过滤
+const filteredIcons = computed(() => {
+  if (!searchKeyword.value.trim()) {
+    return props.icons
+  }
+  
+  const keyword = searchKeyword.value.toLowerCase().trim()
+  return props.icons.filter(icon => 
+    icon.iconName.toLowerCase().includes(keyword) ||
+    icon.collectionName.toLowerCase().includes(keyword) ||
+    icon.iconIdentifier.toLowerCase().includes(keyword)
+  )
+})
+
+// 分页
+const totalPages = computed(() => Math.ceil(filteredIcons.value.length / pageSize.value))
+
+const paginatedIcons = computed(() => {
+  const start = (currentPage.value - 1) * pageSize.value
+  const end = start + pageSize.value
+  return filteredIcons.value.slice(start, end)
+})
+
+const handleSearch = () => {
+  currentPage.value = 1
+}
+
+const handleSelectIcon = (icon: Icon) => {
+  selectedIconIdentifier.value = icon.iconIdentifier
+}
+
+const handlePageChange = (page: number) => {
+  currentPage.value = page
+}
+
+const handleConfirm = () => {
+  if (!selectedIconIdentifier.value) {
+    showToast('请选择一个图标')
+    return
+  }
+  emit('confirm', selectedIconIdentifier.value)
+  handleClose()
+}
+
+const handleCancel = () => {
+  emit('cancel')
+  handleClose()
+}
+
+const handleClose = () => {
+  searchKeyword.value = ''
+  currentPage.value = 1
+  selectedIconIdentifier.value = props.defaultIconIdentifier
+}
+
+// 监听默认图标变化
+watch(() => props.defaultIconIdentifier, (newVal) => {
+  selectedIconIdentifier.value = newVal
+})
+</script>
+
+<style scoped lang="scss">
+.icon-selector {
+  max-height: 70vh;
+  display: flex;
+  flex-direction: column;
+  
+  .icon-list {
+    flex: 1;
+    overflow-y: auto;
+    max-height: 55vh;
+    padding: 16px;
+    display: grid;
+    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
+    gap: 12px;
+    margin-bottom: 16px;
+  }
+  
+  .icon-item {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    padding: 12px;
+    border: 2px solid #e5e7eb;
+    border-radius: 8px;
+    cursor: pointer;
+    transition: all 0.2s;
+    
+    &:hover {
+      border-color: #1989fa;
+      background-color: #f5f5f5;
+    }
+    
+    &.active {
+      border-color: #1989fa;
+      background-color: #e6f7ff;
+    }
+  }
+  
+  .icon-label {
+    font-size: 12px;
+    color: #646464;
+    margin-top: 8px;
+    text-align: center;
+  }
+  
+  .pagination {
+    padding: 16px;
+    border-top: 1px solid #e5e7eb;
+  }
+}
+</style>