feat: add reasoning effort configuration for models

- Support setting reasoning effort via model name suffix
- Add `-high`, `-medium`, and `-low` suffixes to control reasoning effort
- Update README with new model configuration option
- Modify OpenAI adaptor to handle reasoning effort settings

relay/channel/openai/adaptor.go

@@ -117,6 +117,13 @@ func (a *Adaptor) ConvertRequest(c *gin.Context, info *relaycommon.RelayInfo, re
 		if strings.HasPrefix(request.Model, "o3") {
 			request.Temperature = nil
 		}
+		if strings.HasSuffix(request.Model, "high") {
+			request.ReasoningEffort = "high"
+		} else if strings.HasSuffix(request.Model, "low") {
+			request.ReasoningEffort = "low"
+		} else if strings.HasSuffix(request.Model, "medium") {
+			request.ReasoningEffort = "medium"
+		}
 	}
 	if request.Model == "o1" || request.Model == "o1-2024-12-17" || strings.HasPrefix(request.Model, "o3") {
 		//修改第一个Message的内容，将system改为developer