feature/issue-68575: Add bundle_name to Dag

[jroachgolf84]

Description

This PR adds bundle_name to Dag. Per #68575, having bundle_name available would allow for it to be used for things like writing Cluster Policies (snipped of code below).

@hookimpl
def dag_policy(dag: DAG):
    if dag.bundle_name == "example_dags":
        return # skip validating example dags
    if dag.bundle_name == "special_dags":
         ... # special dag policy

closes: #68575

Testing

Three new unit-tests were added as part of this effort. These can be run using the commands below:

breze testing task-sdk-tests task-sdk/tests/task_sdk/definitions/test_dag.py

breeze testing core-tests airflow-core/tests/unit/dag_processing/test_dagbag.py

The below Dag was written to validate that the bundle name was available and correct.

from airflow.sdk import DAG, task
from datetime import datetime

with DAG(
    dag_id="feature_issue_68575",
    start_date=datetime(2026, 1, 1),
    schedule="@once"
) as dag:

    @task
    def output_dag_bundle_name(**context):
        _dag = context.get("dag")
        return _dag.bundle_name

    output_dag_bundle_name()

[github-actions]

uv.lock on main just moved via #68642 ("Prepare provider documentation 2026-06-16"), commit 0236c57 and this PR currently conflicts.

Quickest fix:

git fetch upstream main && git rebase upstream/main
rm uv.lock && uv lock
git add uv.lock && git rebase --continue
git push --force-with-lease

Automated nudge — ignore if you're not ready to rebase. This comment is updated in place on future uv.lock bumps.