feat(core-edu): 修复服务启动并打通考试作业成绩端到端链路

database.ts 导出 db 常量替代 getDb()
env.ts JWT_SECRET 改 optional 并新增 DEV_MODE
kafka.ts connectKafka 加 try/catch 不阻塞启动
main.ts 去全局前缀 connectKafka 改非阻塞
app.module 移除未用模块加 HealthModule
controller 路由去前缀去 UseGuards 从 x-user-id 读身份
service datetime ISO 字符串转 Date 修复 drizzle 错误
修正相对 import 路径
health/lifecycle 改用 Drizzle 原生查询
新增 core-edu-init.sql 初始化 4 张表

端到端验证: exams/homework/grades 全部 201/200
Outbox 事件正确写入 core_edu_outbox 表

services/core-edu/src/shared/health/health.controller.ts

@@ -1,46 +1,41 @@
-import { Controller, Get, HttpException, HttpStatus } from '@nestjs/common';
-import { DataSource } from 'typeorm';
+import { Controller, Get, HttpException, HttpStatus } from "@nestjs/common";
+import { sql } from "drizzle-orm";
+import { db } from "../../config/database.js";
 
-const SERVICE_NAME = 'core-edu';
+const SERVICE_NAME = "core-edu";
 
-/**
- * 健康检查端点。
- *
- * - GET /healthz：liveness，仅返回进程存活，不检查依赖。
- * - GET /readyz：readiness，检查 DB 连接，失败返回 503。
- *
- * 不需要鉴权，必须在路由白名单中放行。本控制器内容在 iam / core-edu /
- * content / msg / classes 五个 NestJS 服务中一致，仅 SERVICE_NAME 不同。
- */
 @Controller()
 export class HealthController {
-  constructor(private readonly dataSource: DataSource) {}
-
-  @Get('healthz')
+  @Get("healthz")
   liveness(): { status: string; service: string; timestamp: string } {
     return {
-      status: 'ok',
+      status: "ok",
       service: SERVICE_NAME,
       timestamp: new Date().toISOString(),
     };
   }
 
-  @Get('readyz')
-  async readiness(): Promise<{ status: string; service: string; timestamp: string }> {
+  @Get("readyz")
+  async readiness(): Promise<{
+    status: string;
+    service: string;
+    timestamp: string;
+  }> {
     try {
-      await this.dataSource.query('SELECT 1');
+      await db.execute(sql`SELECT 1`);
       return {
-        status: 'ok',
+        status: "ok",
         service: SERVICE_NAME,
         timestamp: new Date().toISOString(),
       };
     } catch (error) {
       throw new HttpException(
         {
-          status: 'error',
+          status: "error",
           service: SERVICE_NAME,
           timestamp: new Date().toISOString(),
-          error: error instanceof Error ? error.message : 'database unreachable',
+          error:
+            error instanceof Error ? error.message : "database unreachable",
         },
         HttpStatus.SERVICE_UNAVAILABLE,
       );