Add io event queue fd

[mensfeld]

This PR adds FD IO events for consumer and main queues.

[Copilot]

Pull Request Overview

This PR adds support for IO event notifications on Kafka consumer queues to enable event-driven consumption patterns. It exposes librdkafka's rd_kafka_queue_io_event_enable functionality through new Ruby APIs.

Key changes:

• Added consumer and main queue pointer access methods with proper cleanup
• Implemented IO event enabling functionality with file descriptor notifications
• Added comprehensive test coverage for the new queue APIs

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
lib/rdkafka/consumer.rb	Adds queue pointer methods and IO event enabling with proper resource cleanup
lib/rdkafka/bindings.rb	Exposes new librdkafka queue functions for consumer queue and IO events
spec/lib/rdkafka/consumer_spec.rb	Tests for consumer queue methods and IO event functionality
spec/lib/rdkafka/bindings/queue_spec.rb	Comprehensive integration tests for queue bindings and event-driven patterns
CHANGELOG.md	Documents the new queue IO event notification feature

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[Copilot]

Missing attachment for rd_kafka_queue_get_main function which is used in the consumer implementation but not declared in bindings.

Suggested change

	attach_function :rd_kafka_queue_get_consumer, [:pointer], :pointer
	attach_function :rd_kafka_queue_get_consumer, [:pointer], :pointer
	attach_function :rd_kafka_queue_get_main, [:pointer], :pointer

[Copilot]

Missing require 'fcntl' at the top of the spec file, which is needed for the Fcntl::F_SETFL and Fcntl::O_NONBLOCK constants used throughout the tests.

Suggested change

	require 'spec_helper'
	require 'spec_helper'
	require 'fcntl'