fix: carry the API error body of a failed streaming request

[vdusek]

Follow-up to #1041.

A failed request with responseType: 'stream' (LogClient.stream(), getRecord({ stream: true })) handed an unread IncomingMessage to ApifyApiError. JSON.stringify threw on its circular references, so the message read Unexpected error: [object Object] and the API's type, message and data were lost.

HttpClient now reads a streamed error body into a buffer before building the error, as the Python client does, using concatStreamToBuffer from @apify/utilities. A read that fails mid-body is swallowed: a raw socket error carries no status code, which would break getRecord({ stream: true }) resolving to undefined on a 404. ApifyApiError decodes the buffer once and keeps a non-JSON body as text, so an HTML error page from a proxy is readable instead of a dump of byte values. That last part also improves downloadItems() and getRecord({ buffer: true }) errors.

Known limitation, left as a follow-up: the body read sits outside the axios timeout, because axios settles a stream response at its headers. The agent's socket idle timeout bounds it, measured at 2043 ms under a 2 s client timeout, and maxContentLength: -1 leaves it without a size cap. Tightening either needs a separate error-body budget.

Closes #1043

✍️ Drafted by Claude Code

[github-actions]

⚠️ There are broken links in the documentation.

See more at https://github.com/apify/apify-client-js/actions/runs/34825992263#summary-103918173669

[barjin]

lgtm, thanks 👍