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/server/src/ai-chat/ai-chat.service.ts

@@ -16,6 +16,7 @@ import { AiFormService } from './ai-form.service';
 import { AiReviewService } from './ai-review.service';
 import { AiModelStreamService } from './ai-model-stream.service';
 import { OfficeCliService } from './office-cli.service';
+import { OperationLogsService } from '../operation-logs/operation-logs.service';
 import {
   AiConversation,
   AiMessage,
@@ -72,7 +73,11 @@ import {
   markReviewSubmittedOnMessage,
 } from './ai-chat.submissions';
 import { denyWriteTool, executeTool } from './ai-chat.tools';
-import { executeStartImportWizard } from './ai-chat.tool-actions';
+import {
+  executeExcelAnalyze,
+  executePreflightImport,
+  executeStartImportWizard,
+} from './ai-chat.tool-actions';
 import { executeGeneration } from './ai-chat.generation';
 import {
   assertGeneratedLength,
@@ -108,6 +113,7 @@ export class AiChatService implements AiChatServiceContext {
     readonly excelReader?: AiExcelReaderService,
     readonly officeCli?: OfficeCliService,
     readonly importsService?: ImportsService,
+    readonly opLog?: OperationLogsService,
   ) {}
 
   listSkills(user: AuthenticatedUser): AgentSkillDescriptor[] {
@@ -291,6 +297,24 @@ export class AiChatService implements AiChatServiceContext {
     return executeStartImportWizard(this, messageId, call, context, emit);
   }
 
+  executePreflightImport(
+    messageId: number,
+    call: ModelToolCall,
+    userId: number,
+    emit: AiSseEmitter,
+  ): Promise<string> {
+    return executePreflightImport(this, messageId, call, userId, emit);
+  }
+
+  executeExcelAnalyze(
+    messageId: number,
+    call: ModelToolCall,
+    userId: number,
+    emit: AiSseEmitter,
+  ): Promise<string> {
+    return executeExcelAnalyze(this, messageId, call, userId, emit);
+  }
+
   executeGeneration(input: GenerationInput): Promise<void> {
     return executeGeneration(this, input);
   }