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/content/src/shared/lifecycle/lifecycle.service.ts

@@ -1,13 +1,22 @@
-import { Injectable, Logger } from "@nestjs/common";
+import {
+  Injectable,
+  Logger,
+  OnApplicationShutdown,
+  OnModuleInit,
+} from "@nestjs/common";
 import { closeDb } from "../../config/database.js";
 import { closeNeo4j } from "../../config/neo4j.js";
 
 const SERVICE_NAME = "content";
 
 @Injectable()
-export class LifecycleService {
+export class LifecycleService implements OnModuleInit, OnApplicationShutdown {
   private readonly logger = new Logger(LifecycleService.name);
 
+  onModuleInit(): void {
+    this.logger.log(`service ${SERVICE_NAME} module initialized`);
+  }
+
   async onApplicationShutdown(signal?: string): Promise<void> {
     this.logger.log(
       `service ${SERVICE_NAME} shutting down (signal=${signal ?? "unknown"})`,