feat: update MaxTokens handling

relay/channel/claude/relay-claude.go

@@ -149,7 +149,7 @@ func RequestOpenAI2ClaudeMessage(textRequest dto.GeneralOpenAIRequest) (*dto.Cla
 
 	claudeRequest := dto.ClaudeRequest{
 		Model:         textRequest.Model,
-		MaxTokens:     textRequest.MaxTokens,
+		MaxTokens:     textRequest.GetMaxTokens(),
 		StopSequences: nil,
 		Temperature:   textRequest.Temperature,
 		TopP:          textRequest.TopP,