fix(utils): prevent unhandled error event and clean up timer on request timeout (fixes #34)

[siddiqueirshad]

Fixes #34

Cause

When a request timeout occurs, calling req.destroy() emits an error event on the ClientRequest instance. When the original error listener was detached via req.off("error", ...), Node.js raised an Unhandled 'error' event error, causing unhandled rejections or crashes.

Solution

1. Clear timer references and attach a noop error handler prior to destroying the ClientRequest on timeout.
2. Reject cleanly with RequestTimeoutError without emitting unhandled error events.