feat: [backend] vision support (#1510)

Co-authored-by: Garfield Dai <dai.hai@foxmail.com>

api/fields/conversation_fields.py

@@ -28,6 +28,12 @@ annotation_fields = {
     'created_at': TimestampField
 }
 
+message_file_fields = {
+    'id': fields.String,
+    'type': fields.String,
+    'url': fields.String,
+}
+
 message_detail_fields = {
     'id': fields.String,
     'conversation_id': fields.String,
@@ -43,7 +49,8 @@ message_detail_fields = {
     'from_account_id': fields.String,
     'feedbacks': fields.List(fields.Nested(feedback_fields)),
     'annotation': fields.Nested(annotation_fields, allow_null=True),
-    'created_at': TimestampField
+    'created_at': TimestampField,
+    'message_files': fields.List(fields.Nested(message_file_fields), attribute='files'),
 }
 
 feedback_stat_fields = {
@@ -111,11 +118,6 @@ conversation_message_detail_fields = {
     'message': fields.Nested(message_detail_fields, attribute='first_message'),
 }
 
-simple_model_config_fields = {
-    'model': fields.Raw(attribute='model_dict'),
-    'pre_prompt': fields.String,
-}
-
 conversation_with_summary_fields = {
     'id': fields.String,
     'status': fields.String,
@@ -180,4 +182,4 @@ conversation_with_model_config_infinite_scroll_pagination_fields = {
     'limit': fields.Integer,
     'has_more': fields.Boolean,
     'data': fields.List(fields.Nested(conversation_with_model_config_fields))
-}
+}