style: 全局 UI 主题皮肤重构与样式模块化

引入 Element Plus 主题定制和主题皮肤 composable，将全局
样式拆分为组件级独立 CSS 文件（侧边栏、顶栏、工作台等），
统一色彩变量和间距规范，重构所有视图和组件样式以适配新
主题系统，优化图表和知识图谱组件视觉表现，提取审计和差
旅报销相关子组件。

web/src/components/charts/LogTrendChart.vue

@@ -1,8 +1,8 @@
 <template>
   <div class="log-trend-chart">
     <div class="chart-legend">
-      <span><i style="background:#10b981"></i>日志总量</span>
-      <span><i style="background:#ef4444"></i>失败数</span>
+      <span><i :style="{ background: chartColors.primary }"></i>日志总量</span>
+      <span><i :style="{ background: chartColors.danger }"></i>失败数</span>
     </div>
     <div class="chart-body">
       <Bar :data="chartData" :options="chartOptions" />
@@ -24,6 +24,7 @@ import {
   Legend
 } from 'chart.js'
 import { useAnimationProgress } from '../../composables/useAnimationProgress.js'
+import { useThemeColors } from '../../composables/useThemeColors.js'
 
 ChartJS.register(CategoryScale, LinearScale, BarElement, PointElement, LineElement, Tooltip, Legend)
 
@@ -38,6 +39,11 @@ const progress = useAnimationProgress([
   () => props.totals,
   () => props.failures
 ], 1000)
+const themeColors = useThemeColors()
+const chartColors = computed(() => ({
+  primary: themeColors.value.chartPrimary,
+  danger: themeColors.value.chartDanger
+}))
 
 const scaleSeries = (series) =>
   series.map((value) => Math.round(Number(value || 0) * progress.value))
@@ -50,7 +56,7 @@ const chartData = computed(() => ({
     {
       label: '日志总量',
       data: scaleSeries(props.totals),
-      backgroundColor: '#10b981',
+      backgroundColor: chartColors.value.primary,
       borderRadius: 4,
       barPercentage: 0.58,
       categoryPercentage: 0.56,
@@ -59,11 +65,11 @@ const chartData = computed(() => ({
     {
       label: '失败数',
       data: scaleSeries(props.failures),
-      borderColor: '#ef4444',
+      borderColor: chartColors.value.danger,
       backgroundColor: 'transparent',
       borderWidth: 2,
       pointBackgroundColor: '#ffffff',
-      pointBorderColor: '#ef4444',
+      pointBorderColor: chartColors.value.danger,
       pointBorderWidth: 2,
       pointRadius: 3,
       pointHoverRadius: 5,