Migrate common broker integration tests to DSL

[rajp152k]

Summary

Ports the common Redis/RabbitMQ broker integration scenarios into the new integration test DSL introduced in #214.

Common scenarios now covered through goose.integration.goose-test:

• async execution
• absolute scheduling
• relative scheduling
• middleware execution
• retry flow with custom retry queue
• death handling after retry exhaustion

The older broker-specific integration namespaces have been pruned to retain only broker-specific coverage:

• Redis: orphan recovery and batch jobs
• RabbitMQ: ACK behavior, quorum queues, max-delay scheduling guard, publisher confirms, RMQ metadata, graceful shutdown

This continues the migration tracked in #216 and follows the common abstraction direction discussed in #202. It also leans further into the execution promise/delivery semantics from #214 for middleware/retry/death assertions.

Validation

• clj-kondo --lint bb.edn deps.edn src test --fail-level error
  • no errors; only existing warnings/info
• clj -X:test :nses '[goose.integration.goose-test goose.brokers.redis.integration-test goose.brokers.rmq.integration-test]'
  • Ran 14 tests containing 75 assertions. 0 failures, 0 errors.

[ashutoshgngwr]

LGTM!