feat: 新增预算助手报告组件并优化报销交互细节

新增预算助手报告视图模型和组件，优化报销洞察面板和消息项
样式细节，完善预算中心页面布局和文档中心视图，增强报销创
建会话管理和提交编排器，调整 Vite 构建配置，补充单元测试。

web/src/components/travel/TravelReimbursementMessageItem.vue

@@ -35,6 +35,11 @@
       @click="ui.handleAssistantMarkdownClick($event, message)"
     ></div>
 
+    <BudgetAssistantReport
+      v-if="message.role === 'assistant' && message.budgetReport"
+      :report="message.budgetReport"
+    />
+
     <div
       v-if="message.role === 'assistant' && message.applicationPreview"
       class="application-preview-table"
@@ -427,11 +432,13 @@
 </template>
 
 <script>
+import BudgetAssistantReport from './BudgetAssistantReport.vue'
 import EnterpriseSelect from '../shared/EnterpriseSelect.vue'
 
 export default {
   name: 'TravelReimbursementMessageItem',
   components: {
+    BudgetAssistantReport,
     EnterpriseSelect
   },
   props: {