refactor(wel): 重构欢迎页为模块化组件

- 将欢迎页整体结构拆分为多个功能区组件，提高代码可维护性
- 移除原有欢迎横幅、指标卡、图表区、下方区及快捷入口的静态实现
- 引入并注册 SectionKpi、SectionStructure、SectionBusiness 等八个子组件
- 删除冗余样式，更新整体背景和布局样式
- 精简模板内容，仅保留子组件渲染及页脚版权信息
- 移除无用的响应式数据、计算属性及方法
- 包含依赖包 echarts 的新增，支持后续图表功能开发

src/views/wel/components/section-summary.vue

@@ -0,0 +1,67 @@
+<template>
+  <section class="wel-sec">
+    <el-row :gutter="16">
+      <el-col :xs="24" :md="12">
+        <div class="wel-card summary-panel">
+          <div class="panel-title">
+            车辆耗时占比
+            <span class="panel-title__unit">按小时</span>
+          </div>
+          <wel-chart :option="donutOpt" height="260px" />
+        </div>
+      </el-col>
+      <el-col :xs="24" :md="12">
+        <div class="wel-card summary-panel">
+          <div class="panel-title">
+            单据完成趋势
+            <span class="panel-title__unit">按周</span>
+          </div>
+          <wel-chart :option="lineOpt" height="260px" />
+        </div>
+      </el-col>
+    </el-row>
+  </section>
+</template>
+
+<script>
+import WelChart from './wel-chart.vue';
+import { donutOption, lineAreaOption } from '../chart-options';
+
+export default {
+  name: 'section-summary',
+  components: { WelChart },
+  data() {
+    return {
+      // Mock：车辆耗时与单据完成数据，对接统计接口后替换
+      timeItems: [
+        { name: '在途运输', value: 86.2 },
+        { name: '装货等待', value: 32.5 },
+        { name: '卸货作业', value: 28.4 },
+        { name: '返程空驶', value: 21.6 },
+        { name: '场站等待', value: 18.3 },
+        { name: '维修保养', value: 9.8 },
+      ],
+      weeks: ['1周', '2周', '3周', '4周', '5周', '6周', '7周'],
+      doneData: [520, 545, 508, 532, 560, 548, 572],
+    };
+  },
+  computed: {
+    donutOpt() {
+      return donutOption(this.timeItems, { centerTitle: '196.8', centerSub: '总耗时（小时）' });
+    },
+    lineOpt() {
+      return lineAreaOption(this.weeks, [
+        { name: '完成单据', data: this.doneData, color: '#1a9e94' },
+      ]);
+    },
+  },
+};
+</script>
+
+<style lang="scss" scoped>
+@import '../dashboard.scss';
+
+.summary-panel {
+  margin-bottom: 16px;
+}
+</style>