feat(cli): add airflow dags clear for partition-range reprocessing

[Lee-W]

Why

airflow tasks clear --start-date / --end-date filters by logical_date, so it cannot reach DagRuns whose partition_date diverges from their logical_date (rollup or offset partitions). Today the only way to bulk-reprocess such partitioned runs is N individual API calls or N clicks in the UI.

What

• New airflow dags clear <dag_id> subcommand. Filters DagRuns by DagRun.partition_date against an inclusive [--partition-start, --partition-end] window.
• At least one bound must be provided; an inverted window is rejected. Runs with NULL partition_date are never matched.
• Reuses the existing Dag.clear() engine per matched run_id, so the resulting state transitions (TIs reset, DagRun re-queued) match every other clear path.
• Supports --yes, --only-failed, --only-running, --verbose. No --start-date / --end-date, task-regex, or upstream/downstream — those remain on tasks clear for TI-level workflows.

closes: #65921

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Was generative AI tooling used to co-author this PR?

• Yes — Claude Opus 4.7 (1M context)

Generated-by: Claude Opus 4.7 (1M context) following the
guidelines

---

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[uranusjr]

I wonder what exactly we are looking for when we clear in this context. Do we want to make the old dag run disappear (basically what this does), or do we simply want to mark the partitions as unfulfilled? If the latter, I wonder if it’d be better to have airflow partitions clear instead.

Implementation-wise, I also wonder if it’d make sense to disassociate a dag run with a partition (to “clear” the partition), instead of clearing the run directly.

cc @cmarteepants