fix(client): swallow synchronous EPIPE from writeAfterFIN (#3282)

[nkaradzhov]

net.Socket.write can throw synchronously with code 'EPIPE' on a half-closed socket, before the 'close' event fires. The throw escaped RedisSocket.write from a setImmediate flush and crashed the process. Preflight writable, wrap the cork/write loop in try/finally so uncork always runs, and narrowly swallow EPIPE — the close handler will reject the pending command via #waitingForReply.

Fixes #3282

Description

Describe your pull request here

---

Checklist

• Does npm test pass with this change (including linting)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?

---

Note

Medium Risk
Medium risk because it changes low-level socket write behavior and error handling; mistakes could hide real network failures or affect backpressure/flush behavior under load.

Overview
Prevents process crashes when net.Socket.write throws synchronously on half-closed connections by guarding RedisSocket.write with a writable check, ensuring uncork() always runs via try/finally, and swallowing only EPIPE while rethrowing other errors.

Adds targeted unit tests that capture the underlying net.Socket to verify: no writes occur when the socket is not writable, synchronous EPIPE is ignored, and non-EPIPE errors still surface.

^{Reviewed by Cursor Bugbot for commit 1452cac. Bugbot is set up for automated code reviews on this repo. Configure here.}