defaultChannel shared between setup operations and publish() path

[iifawzi]

Summary

getDefaultChannel() returns the same channel used for assertQueue / bindQueue / assertExchange AND for the public runMQ.publish() path. If a setup operation precondition-fails (e.g., a queue redeclare with mismatched args), RabbitMQ closes the channel — and that's also the channel publishes go through. Subsequent publishes silently fail or throw on a closed channel.

Where

• src/core/RunMQ.ts:137-140 (initialize() uses defaultChannel for setup + holds it for publishes)
• src/core/consumer/RunMQConsumerCreator.ts:94, 142 (assertQueues / bindQueues use defaultChannel)
• src/core/clients/RabbitMQClientAdapter.ts:99-104 (getDefaultChannel)

Failure mode

• A consumer is added with config that conflicts with an existing queue → broker closes the setup channel.
• All publishes from runMQ.publish() now fail because they share that channel.
• Combined with No publisher confirms — silent message drops on broker rejection #28 (no confirms), this is silent.

Proposed fix

• Separate concerns: dedicated channel for setup operations (asserts, binds), dedicated channel for publish.
• Publish channel should ideally be a confirm-channel (see No publisher confirms — silent message drops on broker rejection #28).
• Setup channel can be ephemeral — open per setup operation, close when done.

Acceptance criteria

• Setup-time channel close does not affect the publishing channel.
• Test: induce a queue-redeclare precondition failure → publish path remains healthy.

[iifawzi]

Resolved by #42