fix(adapter-node): skip socket cleanup for cluster workers

[tsushanth]

Fixes #16230.

Root cause

The stale-socket cleanup added in #15449 (released in adapter-node 5.5.7) unconditionally runs on every process startup:

if (fs.statSync(path).size === 0) {
  await rm(path);
}

The size === 0 heuristic is meant to detect a stale socket left over from an unclean shutdown, but a live unix domain socket also reports size = 0. In Node cluster / PM2 cluster mode:

1. The primary process binds and creates the socket file.
2. Each worker process inherits the primary's listening handle (no bind() of its own), runs the same startup code, finds size === 0, and deletes the live socket file.
3. Workers appear healthy (they share the in-kernel listening state), but the socket path is gone from disk — the reverse proxy (e.g. nginx proxy_pass unix:…) can no longer connect. No error, no restart, silent regression.

Fix

Import node:cluster and skip the rm() call when the current process is a cluster worker. Workers inherit the socket handle from the primary and must never manage the socket file. The primary (or any single-process deployment) retains the existing cleanup behaviour unchanged.

cluster.isWorker is false in non-cluster processes, so this change is a no-op for single-process deployments.

[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from 9fd278c:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/9fd278c9ccade1944441c961fcc6f855891b15f8

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/16241

Note

This PR is from a fork. A maintainer must approve approve each commit before it can be built and installed.

[changeset-bot]

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Latest commit: 9fd278c

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