fix: code compliance audit and fix across all services

NestJS (6 services): implement @RequirePermission decorator with
SetMetadata+Reflector, register APP_GUARD globally, fix as assertions
to type guards, add explicit return types, fix import type for express,
fix /metrics implicit any, replace native Error with ApplicationError,
remove typeorm remnants, register LifecycleService.

teacher-bff: add logger, ApplicationError, GlobalErrorFilter, forward
real userId to downstream, log downstream failures, migrate health
controller to shared/health.

Go (2 services): interface to any, doc comments, CORS dev whitelist,
JWT secret fail-fast, push-gateway internal API auth, metrics and
readyz endpoints, remove dead code.

Python (2 services): lifespan return type, dev_mode to bool, data-ana
APIRouter, ai POST body model, ClickHouse async wrapping.

services/teacher-bff/src/main.ts

@@ -1,26 +1,31 @@
 import "reflect-metadata";
 import { NestFactory } from "@nestjs/core";
 import { AppModule } from "./app.module.js";
-import { env } from "./config/env.js";
+import { GlobalErrorFilter } from "./shared/errors/global-error.filter.js";
 import { initTracer, shutdownTracer } from "./shared/observability/tracer.js";
+import { logger } from "./shared/observability/logger.js";
+import { env } from "./config/env.js";
 import { metricsRegistry } from "./shared/observability/metrics.js";
+import type { Request, Response } from "express";
 
 async function bootstrap(): Promise<void> {
   initTracer();
+
   const app = await NestFactory.create(AppModule, {
     logger: ["log", "error", "warn"],
   });
 
+  app.useGlobalFilters(new GlobalErrorFilter());
   app.enableShutdownHooks();
 
   // Prometheus 指标端点：不鉴权，供 Prometheus 抓取。
-  app.getHttpAdapter().get("/metrics", async (_req, res) => {
+  app.getHttpAdapter().get("/metrics", async (_req: Request, res: Response) => {
     res.set("Content-Type", metricsRegistry.contentType);
     res.end(await metricsRegistry.metrics());
   });
 
   await app.listen(env.PORT);
-  console.log(`Teacher BFF started on port ${env.PORT}`);
+  logger.info({ port: env.PORT }, "Teacher BFF started");
 
   process.on("SIGTERM", async () => {
     await app.close();
@@ -29,6 +34,6 @@ async function bootstrap(): Promise<void> {
 }
 
 bootstrap().catch((err: unknown) => {
-  console.error("Failed to start Teacher BFF", err);
+  logger.error({ err }, "Failed to start Teacher BFF");
   process.exit(1);
 });