批量任务队列支持可配置并发执行（默认串行，最高 8 路 worker），创建/编辑队列时可设置 concurrency；采用原子领取与执行器去重，提升多子任务场景下的吞吐与稳定性。同步修复任务管理中的若干边界问题（执行中删除保护、取消卡住清理、单条重跑状态收口等）。
Batch task queues now support configurable concurrent execution (default serial, up to 8 workers). Set concurrency when creating or editing a queue; tasks are claimed atomically with executor deduplication for safer parallel runs. Also fixes several task-management edge cases, including delete guards while executing, stuck-cancel cleanup, and single-task rerun state handling.