Add RabbitMqConsumerFactory tests and enhance CloseReason?.CancellationToken coverage

- Add comprehensive unit tests for RabbitMqConsumerFactory including QoS and queue name derivation
- Add tests verifying CloseReason?.CancellationToken pattern in consumer Ack/Nack operations
- Add test for cancellation token forwarding in publisher
- Add bounded channel overflow test for SseStream with DropOldest behavior
- Refactor SseStream to use bounded channels (capacity: 100) with DropOldest backpressure
- Remove outdated .editorconfig.IDEAL and CLAUDE.md files

Author: ANcpLua