✨ Delete key ceremonies in GUI

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Suggestion

As an admin I want to delete key ceremonies that are in an error state so that guardians don't get confused and join the wrong one

### Possible Implementation

_No response_

### Anything else?

_No response_

該 issue 未指出任何檔案、測試或 GUI 進入點。首先找出 GUI 的金鑰儀式管理流程，並釐清管理員可以刪除哪些處於錯誤狀態的儀式；在實作之前定義完成後的行為和驗證步驟。

由索引模型根據 Issue 內容生成。