Reset group mention status

Use setConversation() to clear the group-mention indicator on one group conversation.

import { setConversation } from '@/uni_modules/unix-openim-sdk'

await setConversation({ conversationID, groupAtType: 0 })

Use the contract-defined “no mention” value for groupAtType; do not invent another numeric meaning. Promise success means that the conversation update request completed. Merge the later onConversationChanged snapshot or query the conversation again.

This only changes the conversation's mention prompt. It does not delete @ messages and does not clear unread count. To clear unread state, call Mark a conversation as read separately.