feat: auto-inject OpenLineage parent info into TriggerDagRunOperator conf

[kacpermuda]

TLDR

Automatically inject OpenLineage lineage metadata into triggered DAG run conf when OpenLineage is available and enabled, improving lineage tracking across DAG boundaries.. The implementation never modifies non-OpenLineage parts of conf, gracefully handles all error cases, and preserves original conf if anything goes wrong. Users can opt out by setting openlineage_inject_parent_info=False. Because it's safe and only works for users with enabled OL we can keep default=True.

Built on top of OL feature implemented in #57809

User Impact by Scenario

All Users

• Non-OpenLineage configuration: Never modified under any circumstances
• Error handling: If any exception occurs during injection (import errors, unexpected errors), the original conf is returned and a warning is logged
• Opt-out: Set openlineage_inject_parent_info=False to completely disable this feature

Users with OpenLineage disabled or not installed

• Conf: DAG run conf is never modified
• Overhead: Only a lightweight check to detect if OpenLineage is available (debug-level log message)
• Behavior: Function returns immediately with original configuration unchanged

Users on older OpenLineage Provider versions (< 2.8.0)

• Conf: DAG run conf is never modified
• Logging: An informational log message indicates that injection is not supported and suggests upgrading to apache-airflow-providers-openlineage>=2.8.0
• Behavior: Function catches version incompatibility and returns original configuration unchanged

Users on compatible OpenLineage Provider versions (>= 2.8.0)

• Conf: OpenLineage metadata is added to DagRun conf under the openlineage key
• Existing OpenLineage keys: If you already have openlineage part in your conf, they are preserved and merged (parent/root identifiers are not overwritten if they already exist)
• Behavior: Metadata about the parent task (run ID, job name, namespace, root run info) is injected to enable lineage tracking

Testing

Added comprehensive test coverage for both Airflow 2 and Airflow 3:

• Injection disabled when flag is False
• Provider not accessible scenarios
• Version compatibility checks (older vs newer versions)
• Exception handling during injection
• Successful injection with various configuration types (None, empty dict, dict with existing keys)

All tests follow consistent patterns with parametrization and helper functions for maintainability.

Also saved trigger_run_id as TriggerDagRunOperator's attribute to be used by OL listener.

---

^ Add meaningful description above
Read the Pull Request Guidelines for more information.
In case of fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in a newsfragment file, named {pr_number}.significant.rst or {issue_number}.significant.rst, in airflow-core/newsfragments.

[kacpermuda]

The deferral mode may not work until this is merged.

[kacpermuda]

Sorry for the noise, apparently any change to dev/breeze/tests/test_selective_checks.py triggers a lot of codeowners.