Address review feedback on PR #68012

Fix the CI failures and review comments from PR #68012:
- Remove the dead module-level VersionBundle construction in
  schema/versions/__init__.py that referenced names only imported
  under TYPE_CHECKING, breaking the lazy cadwyn import on any access
  to the module and causing NameError in ~30 task-sdk tests.
- Remove a duplicated old_ver_client fixture and import block that
  had been pasted into test_task_instances.py, which triggered
  mypy no-redef and ruff F811/E402 failures in Static checks.
- Use func.min(start_date) instead of ordering by TaskReschedule.id
  when computing the first reschedule start date, since insertion
  order does not guarantee chronological order.

Author: hkc-8010

airflow-core/src/airflow/api_fastapi/execution_api/routes/task_instances.py

@@ -299,10 +299,7 @@ def ti_run(
         first_task_reschedule_start_date = None
         if task_reschedule_count > 0:
             first_task_reschedule_start_date = session.scalar(
-                select(TaskReschedule.start_date)
-                .where(TaskReschedule.ti_id == task_instance_id)
-                .order_by(TaskReschedule.id.asc())
-                .limit(1)
+                select(func.min(TaskReschedule.start_date)).where(TaskReschedule.ti_id == task_instance_id)
             )
 
         dr.team_name = get_team_name_for_ti(task_instance_id, session)

airflow-core/tests/unit/api_fastapi/execution_api/versions/v2026_06_30/test_task_instances.py

@@ -29,19 +29,6 @@
 
 pytestmark = pytest.mark.db_test
 
-
-@pytest.fixture
-def old_ver_client(client):
-    """Last released execution API before first_task_reschedule_start_date was added."""
-import pytest
-
-from airflow._shared.timezones import timezone
-from airflow.utils.state import DagRunState, State
-
-from tests_common.test_utils.db import clear_db_runs
-
-pytestmark = pytest.mark.db_test
-
 TIMESTAMP_STR = "2024-09-30T12:00:00Z"
 TIMESTAMP = timezone.parse(TIMESTAMP_STR)
 PARTITION_DATE = timezone.parse("2026-05-20T01:00:00")
@@ -111,6 +98,8 @@ def test_first_task_reschedule_start_date_removed_from_previous_version(
     result = response.json()
     assert result["task_reschedule_count"] == 1
     assert "first_task_reschedule_start_date" not in result
+
+
 class TestPartitionDateFieldBackwardCompat:
     @pytest.fixture(autouse=True)
     def _freeze_time(self, time_machine):

task-sdk/src/airflow/sdk/execution_time/schema/versions/__init__.py

@@ -20,11 +20,6 @@
 import functools
 from typing import TYPE_CHECKING, Any
 
-bundle = VersionBundle(
-    HeadVersion(),
-    # First supervisor schema version; there is no previous version to migrate from.
-    Version("2026-06-16"),
-)
 if TYPE_CHECKING:
     from cadwyn import VersionBundle