feat: Excel 导入预检与动态问答，AI 聊天/文件解析体验修复

- imports: 新增 preflight_import 预检报告（判定/分阶段统计/阻断归因/问题/下一步/错误示例），导入任务 settings 落库（映射/校区/更新/重复/未匹配策略），预览应用策略，向导提交写操作日志
- ai-chat: 新增 excel_analyze（ExcelJS）工具，移除附件/上下文截断，start_import_wizard 支持确认参数，ui.import_preflight SSE，预览确认写操作日志
- admin: ImportPreflightCard 渲染与持久化，聊天抽屉布局/侧边栏修复，考勤页 CSS 引入，费用/学生页接口 schema 校验修复

apps/admin/src/components/AiChat/AiMessageContent.tsx

@@ -16,6 +16,7 @@ import { useUserStore } from '../../store/user/userStore';
 import { DynamicChart } from './DynamicChart';
 import { DynamicForm } from './DynamicForm';
 import { DynamicReview } from './DynamicReview';
+import { ImportPreflightCard } from './ImportPreflightCard';
 import { LiteCodeHighlighter } from './LiteCodeHighlighter';
 import { LiteMermaid } from './LiteMermaid';
 import type {
@@ -24,6 +25,7 @@ import type {
   AiChatMessageStatus,
   AiChartSchema,
   AiFormSchema,
+  AiImportPreflight,
   AiImportWizard,
   AiReviewSection,
   AiReviewSchema,
@@ -43,6 +45,7 @@ const toolLabels: Record<string, string> = {
   render_form: '生成表单',
   render_review: '生成导入预览',
   render_chart: '生成图表',
+  preflight_import: '导入预检',
   start_import_wizard: '生成导入向导',
   create_student: '创建学生',
   search_exams: '查询考试',
@@ -311,6 +314,11 @@ export const AiMessageContent: React.FC<AiMessageContentProps> = ({
           {attachmentCards}
         </Flex>
       )}
+      {(() => {
+        const preflight = message.metadata?.a2uiImportPreflight;
+        if (!preflight || typeof preflight !== 'object' || Array.isArray(preflight)) return null;
+        return <ImportPreflightCard preflight={preflight as AiImportPreflight} />;
+      })()}
       {(() => {
         const wizard = message.metadata?.a2uiImportWizard as AiImportWizard | undefined;
         if (!wizard || !onOpenImportWizard) return null;