Cocotais Bot has builtin .echo command injection

Cocotais Bot is a QQ official robot framework based on qq-bot-sdk. Starting in version 1.5.0-test2-hotfix and prior to version 1.6.2, command echoing feature in the framework allows users to indirectly trigger privileged behavior by injecting special platform tags. Specifically, an unauthorized user can use the `/echo <qqbot-at-everyone />` command to cause the bot to send a message that mentions all members in the chat, bypassing any permission controls. This can lead to spam, disruption, or abuse of notification systems. Version 1.6.2 contains a patch for the issue.