feat(relay): Add Xinference channel support

relay/constant/api_type.go

@@ -31,6 +31,7 @@ const (
 	APITypeVolcEngine
 	APITypeBaiduV2
 	APITypeOpenRouter
+	APITypeXinference
 	APITypeDummy // this one is only for count, do not add any channel after this
 )
 
@@ -89,6 +90,8 @@ func ChannelType2APIType(channelType int) (int, bool) {
 		apiType = APITypeBaiduV2
 	case common.ChannelTypeOpenRouter:
 		apiType = APITypeOpenRouter
+	case common.ChannelTypeXinference:
+		apiType = APITypeXinference
 	}
 	if apiType == -1 {
 		return APITypeOpenAI, false