feat(infra): p6 hardening - observability and deploy compose

- 5 NestJS services add /metrics endpoint via app.getHttpAdapter()
- prometheus.yml scales to 8 services with rule_files and alertmanager
- monitoring compose replaces blackbox with Loki+Promtail
- Grafana datasource adds Loki
- docker-compose.deploy.yml scales to 11 services
- deploy.env.example completes Neo4j/ES/ClickHouse/LLM vars
- teacher-bff adds health.controller
- CI removes continue-on-error on lint step
- teacher-portal lint script changed to eslint src

services/teacher-bff/src/app.module.ts

@@ -1,7 +1,9 @@
-import { Module } from '@nestjs/common';
-import { TeacherModule } from './teacher/teacher.module.js';
+import { Module } from "@nestjs/common";
+import { TeacherModule } from "./teacher/teacher.module.js";
+import { HealthController } from "./health.controller.js";
 
 @Module({
   imports: [TeacherModule],
+  controllers: [HealthController],
 })
 export class AppModule {}