feat: Support for Chat Flow & Agent Support for binding a single chat flow (#765)

Co-authored-by: Yu Yang <72337138+tomasyu985@users.noreply.github.com>
Co-authored-by: zengxiaohui <csu.zengxiaohui@gmail.com>
Co-authored-by: lijunwen.gigoo <lijunwen.gigoo@bytedance.com>
Co-authored-by: lvxinyu.1117 <lvxinyu.1117@bytedance.com>
Co-authored-by: liuyunchao.0510 <liuyunchao.0510@bytedance.com>
Co-authored-by: haozhenfei <37089575+haozhenfei@users.noreply.github.com>
Co-authored-by: July <jiangxujin@bytedance.com>
Co-authored-by: tecvan-fe <fanwenjie.fe@bytedance.com>

backend/api/model/crossdomain/modelmgr/modelmgr.go

@@ -13,6 +13,7 @@ type LLMParams struct {
 	EnableChatHistory bool           `json:"enableChatHistory"`
 	SystemPrompt      string         `json:"systemPrompt"`
 	ResponseFormat    ResponseFormat `json:"responseFormat"`
+	ChatHistoryRound  int64          `json:"chatHistoryRound"`
 }
 
 type ResponseFormat int64