EventBus: auto-reconnect RabbitMQ consumer

[adedw]

What to build

RabbitMQEventBus (CommentMap.EventBus, ported from eShop) does not restore the consumer after a RabbitMQ connection loss: the channel and subscriptions die until the process restarts. Implement persistent-connection behavior: handle ConnectionShutdownAsync / CallbackExceptionAsync, recreate the channel, re-declare topology and re-run BasicConsumeAsync for all DI subscriptions (see the eShopOnContainers DefaultRabbitMQPersistentConnection approach).

Acceptance criteria

• Restarting the messaging RabbitMQ container mid-session does not permanently kill the consumer: email-sender reconnects, re-declares topology and re-subscribes automatically.
• A confirmation email published during the outage window is processed after recovery (no process restart).
• Reconnect uses bounded backoff, logs reconnect attempts, and does not spam unbounded exceptions.

Blocked by

None (can start immediately).