feat: 将用户提示词作为独立字段传递

重构用户提示词的传递方式，将其从嵌入到 userForm 中改为 ComposeCallbackReq 的独立字段 UserPrompt

workflow/service/flow/lambda_node_util.go

@@ -98,11 +98,6 @@ func GetModelInfo(ctx context.Context, req *flowDto.GetModelInfoReq) (res *flowD
 }
 
 func GetComposeResult(ctx context.Context, buildType int, modelName, promptContent, skillName string, form []map[string]any, userForm []map[string]any, fileUrl []string, sessionId, nodeId string, cause string) (res *flowDto.ComposeCallbackReq, err error) {
-	if !g.IsEmpty(promptContent) {
-		userForm = append(userForm, map[string]any{
-			"prompt": promptContent,
-		})
-	}
 	var callbackUrl = utils.GetCallbackURL(ctx, "/flow/execution/composeCallBack")
 	var consult = make([]flowDto.Consult, 0)
 	var collectFileUrls func(val any) (fullyConsumed bool)
@@ -169,6 +164,7 @@ func GetComposeResult(ctx context.Context, buildType int, modelName, promptConte
 		Cause:       cause,
 		Form:        form,
 		UserForm:    newUserForm,
+		UserPrompt:  promptContent,
 		Consult:     consult,
 		SessionId:   sessionId,
 		NodeId:      nodeId,