def flag_dirty_neighbors(
    driver: GraphDatabase,
    node_id: str,
    reason: str,
) -> list[str]:
    """
    Flag the direct neighbors of a node for consistency recheck
    in the next ingestion cycle.
    """
    with driver.session() as session:
        result = session.run("""
            MATCH (n:Entity {id: $node_id})-[*1]-(neighbor:Entity)
            WHERE NOT neighbor.id = $node_id
            SET neighbor.dirty = true,
                neighbor.dirty_reason = $reason,
                neighbor.dirty_at = datetime()
            RETURN collect(DISTINCT neighbor.id) AS neighbor_ids
        """, node_id=node_id, reason=reason)
        return result.single()["neighbor_ids"]