fix(base): keep prefetchCount default when config.channel is empty

[arsalan507]

Summary

Fixes #30.

RabbitMQBase's constructor built the merged config as:

this.config = {
  channel: { prefetchCount: 1 },
  ...config
}

Because ...config is a top-level spread, any caller-supplied channel key — even a present-but-empty channel: {} — replaces the default object wholesale instead of merging into it. prefetchCount is silently dropped, and channel.prefetch(this.config.channel!.prefetchCount!) in Consumer.connect() ends up calling channel.prefetch(undefined).

Fix

Merge channel key-by-key instead of spreading the whole config over the default:

this.config = {
  ...config,
  channel: { prefetchCount: 1, ...config.channel }
}

Now the default only fills in keys the caller didn't set, matching the merge convention already used for queue arguments in registerQueue().

Test plan

• Added a regression test (tests/consumer.test.ts) that constructs a consumer with channel: {} and asserts channel.prefetch is called with the default 1. Verified it fails against the pre-fix code (channel.prefetch called with undefined) and passes after the fix.
• Added a companion test asserting an explicit prefetchCount still overrides the default.
• pnpm lint, pnpm typecheck, pnpm test (77 passing), pnpm build all green.

[arsalan507]

Friendly ping — the CI runs on #54, #55 and #56 are all sitting at action_required (first-time-contributor workflow approval), so the required ci check can't report. If you approve the workflow runs they should go green on their own; each PR is scoped to a single issue (#30, #27, #28) with a regression test verified failing before the fix and passing after. Happy to rebase or split further if that's easier to review.

[arsalan507]

Hi Igor — thanks again for the #385 review, and for the GB9 catch. I'd have carried that mislabelled fixture forward otherwise.

While you're in this corner of things: #54, #55 and #56 here are still waiting on the first-time-contributor workflow approval, so CI has never actually run on any of them. There's nothing to review yet — it's one click on "Approve and run workflows" and they'll either go green or tell us something useful.

They're small and independent: #54 restores the prefetchCount default when a caller passes channel: {}, #55 stops disconnect() re-arming the reconnect loop, #56 attaches the missing 'error' listeners on connections and channels. Each has a regression test that fails on main.

No rush if this repo isn't a priority right now — just flagging that they're stuck on the gate rather than on anything I can do from my side.