Add a user to the blacklist

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

await addBlack({ toUserID: 'user_b', ex: '' })

Confirm through onBlackAdded or a fresh blacklist snapshot. Never store tokens, private moderation evidence, or administrator-only data in ex. Adding a blacklist entry does not delete local history; conversation hiding and friendship removal are separate operations.