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/BarChart.vue

@@ -28,12 +28,22 @@ import {
   BarElement,
   Tooltip
 } from 'chart.js'
+import { resolveCssColor, useThemeColors } from '../../composables/useThemeColors.js'
 
 ChartJS.register(CategoryScale, LinearScale, BarElement, Tooltip)
 
 const props = defineProps({
   items: { type: Array, required: true }
 })
+const themeColors = useThemeColors()
+const resolvedItems = computed(() => {
+  const fallback = themeColors.value.chartPrimary
+
+  return props.items.map((item) => ({
+    ...item,
+    resolvedColor: resolveCssColor(item.color, fallback)
+  }))
+})
 
 const medalClass = (idx) => {
   if (idx === 0) return 'gold'
@@ -56,10 +66,10 @@ const formatValue = (value) => {
 }
 
 const chartData = computed(() => ({
-  labels: props.items.map((i) => i.name || i.shortName),
+  labels: resolvedItems.value.map((i) => i.name || i.shortName),
   datasets: [{
-    data: props.items.map((i) => i.value || i.amount),
-    backgroundColor: props.items.map((i) => i.color),
+    data: resolvedItems.value.map((i) => i.value || i.amount),
+    backgroundColor: resolvedItems.value.map((i) => i.resolvedColor),
     borderRadius: 6,
     borderSkipped: false,
     barPercentage: 0.7,
@@ -169,4 +179,4 @@ const chartOptions = {
   position: relative;
   height: 240px;
 }
-</style>
+</style>