feat(infra): add OTel auto-instrumentations across all services

NestJS 6 services use getNodeAutoInstrumentations().

Python 2 services use FastAPIInstrumentor. Go 2 services use otelgin.

services/core-edu/src/shared/observability/tracer.ts

@@ -1,29 +1,31 @@
-import { NodeSDK } from '@opentelemetry/sdk-node';
-import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-http';
-import { env } from '../../config/env.js';
-import { logger } from './logger.js';
+import { getNodeAutoInstrumentations } from "@opentelemetry/auto-instrumentations-node";
+import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-http";
+import { NodeSDK } from "@opentelemetry/sdk-node";
+import { env } from "../../config/env.js";
+import { logger } from "./logger.js";
 
 let sdk: NodeSDK | undefined;
 
 export function initTracer(): void {
   if (!env.OTEL_EXPORTER_OTLP_ENDPOINT) {
-    logger.warn('OTEL_EXPORTER_OTLP_ENDPOINT not set, tracing disabled');
+    logger.warn("OTEL_EXPORTER_OTLP_ENDPOINT not set, tracing disabled");
     return;
   }
   sdk = new NodeSDK({
-    serviceName: 'core-edu',
+    serviceName: "core-edu",
     traceExporter: new OTLPTraceExporter({
       url: `${env.OTEL_EXPORTER_OTLP_ENDPOINT}/v1/traces`,
     }),
+    instrumentations: [getNodeAutoInstrumentations()],
   });
   sdk.start();
-  logger.info('OpenTelemetry tracer initialized');
+  logger.info("OpenTelemetry tracer initialized with auto-instrumentations");
 }
 
 export async function shutdownTracer(): Promise<void> {
   if (sdk) {
     await sdk.shutdown();
     sdk = undefined;
-    logger.info('OpenTelemetry tracer shutdown');
+    logger.info("OpenTelemetry tracer shutdown");
   }
 }