[Bug]: Backend child crashes with setTypeOfService EINVAL and restart-loops on macOS

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

1. macOS, T3 Code Alpha desktop app, left running with a normal workspace open.
2. Wait a few minutes without interacting.
3. A banner appears: ": Failed to connect. Reconnecting..." with
   "Failed to fetch remote environment endpoint
   http://127.0.0.1:3773/.well-known/t3/environment (HttpClientError:
   Transport error)".
4. The banner clears on its own, then reappears roughly every minute or two.

Confirming it's a crash rather than a network blip:
ps aux | grep "apps/server/dist/bin.mjs"
The backend PID differs from the one that was running at app launch, and
its start time is later than the main app process.

Expected behavior

The backend child stays up for the life of the desktop session. If it does
die, the UI should say the backend crashed rather than reporting a
connection problem.

Actual behavior

The backend child process exits with an uncaught exception and is
respawned. Each crash/respawn cycle surfaces as a "Failed to connect.
Reconnecting..." banner.

The crash is in Node's bundled undici HTTP client calling the new
net.Socket#setTypeOfService API (nodejs/node#61503), which returns EINVAL
on macOS. It throws synchronously from a socket event handler, so nothing
catches it and the process exits with code 1.

This is not T3 Code's own code, but two things here are in scope:

1. An uncaught exception in the backend child takes down the process and
   leaves the app in a restart loop with no surfaced diagnosis.
2. The user-facing banner reports a transport/connection failure, which
   sends users looking at networking and saved environments instead of
   at a crashing child process.

Pinning or patching the bundled Node/undici would also avoid it.

Impact

Major degradation or frequent failure

Version or commit

0.0.38

Environment

macOS 27 beta 8

Logs or stack traces

Error: setTypeOfService EINVAL
    at Socket.setTypeOfService (node:net:684:13)
    at writeH1 (node:internal/deps/undici/undici:8022:16)
    at Object.write (node:internal/deps/undici/undici:7758:18)
    at _resume (node:internal/deps/undici/undici:9656:54)
    at resume (node:internal/deps/undici/undici:9589:7)
    at Client.<computed> (node:internal/deps/undici/undici:9370:35)
    at node:internal/deps/undici/undici:9539:26
    at Socket.<anonymous> (node:internal/deps/undici/undici:3342:13)
    at Object.onceWrapper (node:events:630:28)
    at Socket.emit (node:events:509:28) {
  errno: -22,
  code: 'EINVAL',
  syscall: 'setTypeOfService'
}

Node.js v24.18.1

{"message":"backend child process failure output end","level":"ERROR",
 "annotations":{"component":"desktop-backend-child","instanceId":"primary",
 "phase":"END","details":"pid=<pid> code=1"}}

Full log: ~/.t3/userdata/logs/server-child.log

Screenshots, recordings, or supporting files

No response

Workaround

None found. The app recovers on its own after each restart, but the
interruption recurs. Switching Node runtimes isn't possible in a packaged
build.

Start in apps/desktop by tracing backend child supervision and the reconnect banner, then reproduce the macOS failure and inspect ~/.t3/userdata/logs/server-child.log. Review the apps/server/dist/bin.mjs entry point and the reported Node/undici stack. Done means the child failure is diagnosed and the UI no longer presents a recurring crash as only a transport connection problem.