config: Add OTEL setup for NextJS

[blarghmatey]

What are the relevant tickets?

N/A

Description (What does it do?)

Adds OTEL integration for the NextJS app so that we can capture tracing data for it in Grafana.

How can this be tested?

Run the app and verify that it starts generating trace spans

Additional Context

We have OTel tracing enabled in the Django layer but not yet in the NextJS. Adding it to the frontend will help provide more end-to-end context of requests throughout our application layers.

[Copilot]

Pull Request Overview

Adds OpenTelemetry (OTEL) integration to the NextJS frontend application to enable distributed tracing capabilities, providing better observability alongside the existing Django backend tracing.

• Integrates Vercel's OTEL package for NextJS instrumentation
• Adds OTEL initialization to the existing instrumentation setup
• Includes necessary OpenTelemetry dependencies for comprehensive tracing

Reviewed Changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 1 comment.

File	Description
frontends/main/src/instrumentation.ts	Adds OTEL registration with service name configuration
frontends/main/package.json	Adds OpenTelemetry and Vercel OTEL dependencies

[ChristopherChudzicki]

@blarghmatey I tried to get this to work locally today. There seems to be some interaction between Sentry and @vercel/otel going on. After failing to get data into into otel-lgtm locally, I tried simply using ConsoleSpanExporter:

export async function register() {
  if (process.env.NEXT_RUNTIME === "nodejs") {
    await import("../sentry.server.config")
  }

  const serviceName = process.env.OTEL_SERVICE_NAME || "mitlearn-frontend"
  registerOTel({ serviceName, traceExporter: new ConsoleSpanExporter() })
}

This logs nothing. But when the sentry code is removed, it starts behaving as expected. I haven't looked into the conflict too much, but did notice these two issues on Sentry's github:

• Problems with Next.js SDK + OTEL getsentry/sentry-javascript#11046
• Have better interop with @vercel/otel getsentry/sentry-javascript#17273

As a first / separate step, probably worth updating Sentry's SDK.