Add IBM MQ provider

[dabla]

With the introduction of event-driven scheduling and the MessageQueueProvider abstraction in Airflow, it has become significantly easier to trigger DAGs from external message brokers as described in Astronomer's guide on event-driven scheduling.

Many enterprises still rely heavily on IBM MQ as their primary enterprise messaging backbone. However, at the moment there is no official Airflow provider supporting IBM MQ.

This implementation consists of:

• An IBMMQHook
• A MessageQueueProvider implementation for IBM MQ
• The ability to trigger DAGs from IBM MQ events
• Standard producer/consumer patterns from within tasks

This allows IBM MQ to function similarly to Kafka, SQS, etc., within the Airflow event-driven scheduling framework.

The implementation is built on top of the open-source IBM MQ Python wrapper:

• IBM MQ Python ibmmq library

IBM has recently released and documented their modern Python binding here:

https://community.ibm.com/community/user/blogs/dylan-goode/2025/10/16/new-python-binding-for-ibm-mq

The hook supports:

• Secure connections (TLS) (to be done)
• Queue get/put operations
• Configurable polling behaviour

The MessageQueueProvider implementation integrates with Airflow's event-driven scheduling so that DAGs can be triggered based on IBM MQ messages.

Why this might make sense:

• IBM MQ is still widely used in regulated industries (banking, insurance, government).
• Many enterprises using Airflow also run IBM MQ.
• This would allow IBM MQ to be a first-class citizen in Airflow's event-driven ecosystem.
• The dependency is officially maintained by IBM and open source.

I am willing to act as initial maintainer and code owner, of course this is purely a proposition.

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[vincbeck]

Since this PR needs approval the community, maybe put in draft to avoid any accidental merge?

[jscheffl]

Looks good for me. Would you add yourself as CODEOWNER for this? Do you know somebody (even non committer) which would help as steward?