kit [PoC] feat: Add support for server-side instrumentation

See https://github.com/sveltejs/kit/discussions/13775

This PR adds minimal adaption for SvelteKit to support registering ESM server-side instrumentation in a dedicated instrument.server.ts file prior to SvelteKit's server being bootstrapped.

Concrete changes:

@sveltejs/kit
- add instrument.server.(js|ts) to file output (s.t. it can be transpiled)
@sveltejs/adapter-node
- add transpiled instrument.server.js to secondary server build
- add dynamic import of instrument.server.js (if available) to server entry

Usage

// instrument.server.ts

// add arbitrary instrumentation code here, for example:
import { NodeSDK } from "@opentelemetry/sdk-node";
import { getNodeAutoInstrumentations } from "@opentelemetry/auto-instrumentations-node";
import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-proto";
import { createAddHookMessageChannel } from "import-in-the-middle";
import { register } from "module";

const { registerOptions, waitForAllMessagesAcknowledged } =
  createAddHookMessageChannel();
register("import-in-the-middle/hook.mjs", import.meta.url, registerOptions);

const sdk = new NodeSDK({
  serviceName: "demo-todo-app",
  traceExporter: new OTLPTraceExporter(),
  instrumentations: [getNodeAutoInstrumentations()],
});

sdk.start();

await waitForAllMessagesAcknowledged();

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[ ] Ideally, include a test that fails without this PR but passes with it.

Tests

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Edits

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May 08 '25 08:05 Lms24

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Latest commit: 09f27746dfda72ad8436ec6c6d1a4c55b3d4764b

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