中文: 修复空牌组清理时错误读取 Anki deck 统计的问题，改为按真实返回结构识别空牌组；同时增强清理弹窗，新增全选、全部不选、反选、已选计数和删除按钮禁用逻辑。
English: Fix empty-deck cleanup by matching Anki deck stats from the real response shape, and improve the cleanup modal with select all, clear all, invert selection, selection counts, and disabled delete when nothing is selected.
Introduced two new management commands: 'Clear currently synced cards' to reset sync state for the current file, and 'Cleanup empty decks' to remove unused decks from Anki. Both commands improve plugin maintenance and synchronization flow.
新增两个管理命令：'清空当前文件已同步卡片'用于重置当前文件的同步状态，'清理空牌组'用于从 Anki 中移除未使用的牌组。这两个命令改进了插件的维护和同步流程。
