会话草稿与提及

suspend fun setDraft(sessionId: String, text: String): BimConversationDraft?
suspend fun clearDraft(sessionId: String)
suspend fun getDraft(sessionId: String): BimConversationDraft?
suspend fun getDrafts(sessionIds: List<String>): List<BimConversationDraft>
suspend fun getMentions(sessionId: String, includeCleared: Boolean = false): List<BimConversationMention>
suspend fun getMentions(sessionIds: List<String>, includeCleared: Boolean = false): List<BimConversationMention>
suspend fun clearMention(sessionId: String, messageId: String)
suspend fun clearMentionsThrough(sessionId: String, deliverySeq: Long)

val service = BimImManager.getInstance().conversationService
service.setDraft("session-1", "稍后回复")
val draft = service.getDraft("session-1")
val mentions = service.getMentions("session-1")
mentions.firstOrNull()?.let { service.clearMention("session-1", it.messageId) }
service.clearDraft("session-1")

空草稿通过 clearDraft 清除。提及记录包含消息 ID、deliverySeq、类型和清除状态；BimConversation.hasAtMe 只是兼容投影。