fix(commons): read the HTTP error response off the original axios error

[mfal]

Problem

Request.execute() caught a rejection and did:

const error = AxiosError.from(e);
if (error.isAxiosError && error.response) {
  return error.response as unknown as ResponsePromise<TOp>;
}
throw e;

The comment above it claimed this preserves the previous behavior of returning the response even for HTTP errors. It could not: AxiosError.from(error, code, config, request, response) builds a fresh AxiosError and assigns response only from its own fifth argument, which was not passed here. So error.response was always undefined and the method always rethrew.

Confirmed against the installed axios 1.15.2 (node_modules/axios/lib/core/AxiosError.js):

const orig = Object.assign(new AxiosError("Not Found"), { response: { status: 404 } });
AxiosError.from(orig).response // => undefined

Today this is masked because buildAxiosConfig() sets validateStatus: () => true, so axios never rejects on an HTTP status in the first place — the branch was dead code that would not have protected the intended behavior if that option were ever changed or overridden by a caller's axios config.

Change

Read the response off the original error using axios' named isAxiosError() type guard, keeping the fallback as live code:

if (isAxiosError(e) && e.response) {
  return e.response as unknown as ResponsePromise<TOp>;
}

The type guard also narrows e, so no cast on the error is needed. The comment is reworded to describe the actual arrangement: validateStatus: () => true is the primary mechanism, and this branch is the fallback for callers that override it.

Passing e.response back into AxiosError.from would just rebuild an error object we immediately discard; dropping the branch entirely would make the "return all responses" contract depend solely on no caller ever overriding validateStatus.

Tests

Request.test.ts gains an error handling block covering three cases: the response is returned, an axios error without a response is rethrown, and a non-axios error is rethrown. requestFn had to be typed — an untyped jest.fn() from @jest/globals infers never args and rejects mockRejectedValue.

Verified the new test is not vacuous: with the old AxiosError.from code restored, returns an axios error's response instead of throwing fails (1 failed, 19 passed); with the fix all 20 pass.

yarn nx run @mittwald/api-client-commons:test --skip-nx-cache   # 3 suites, 20 tests, green
yarn nx run @mittwald/api-client-commons:lint --skip-nx-cache   # clean

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