fix: 全部TS错误修复(25->0) + 证书API 500修复 + i18n缺失key补全 + 类型定义修正

- 证书API 500修复: AssessmentCertificate实体注册到app.module.ts
- 前端TS错误25个清零: i18n key 17个, 类型定义8个
- i18n补全: 17个缺失key添加到zh/en/ja
- KnowledgeFile类型: 添加title, content字段
- importService: 改用apiClient.request替代raw fetch
- ModeSelector: 移除jsx prop
- questionBankService: .ok -> .status >= 400
- NotebookDetailView: .filter -> .items.filter
- ImportTasksDrawer: tasks.items提取
- API端点审计: 16/16通过
- 数据库Schema审计: 25表288列一致
- AGENTS.md更新

server/src/app.module.ts

@@ -58,6 +58,7 @@ import { AdminModule } from './admin/admin.module';
 import { FeishuModule } from './feishu/feishu.module';
 import { FeishuBot } from './feishu/entities/feishu-bot.entity';
 import { FeishuAssessmentSession } from './feishu/entities/feishu-assessment-session.entity';
+import { AssessmentCertificate } from './assessment/entities/assessment-certificate.entity';
 
 @Module({
   imports: [
@@ -100,6 +101,7 @@ import { FeishuAssessmentSession } from './feishu/entities/feishu-assessment-ses
           ApiKey,
           FeishuBot,
           FeishuAssessmentSession,
+          AssessmentCertificate,
         ],
         synchronize: true, // Auto-create database schema. Disable in production.
       }),