fix(aistudio): strip Gemini generation config overrides

Remove generationConfig.maxOutputTokens, generationConfig.responseMimeType and generationConfig.responseJsonSchema from the Gemini payload in translateRequest so we no longer send unsupported or conflicting response configuration fields. This lets the backend or caller control response formatting and output limits and helps prevent potential API errors caused by these keys.

internal/runtime/executor/aistudio_executor.go

@@ -319,6 +319,9 @@ func (e *AIStudioExecutor) translateRequest(req cliproxyexecutor.Request, opts c
 	payload = util.StripThinkingConfigIfUnsupported(req.Model, payload)
 	payload = fixGeminiImageAspectRatio(req.Model, payload)
 	payload = applyPayloadConfig(e.cfg, req.Model, payload)
+	payload, _ = sjson.DeleteBytes(payload, "generationConfig.maxOutputTokens")
+	payload, _ = sjson.DeleteBytes(payload, "generationConfig.responseMimeType")
+	payload, _ = sjson.DeleteBytes(payload, "generationConfig.responseJsonSchema")
 	metadataAction := "generateContent"
 	if req.Metadata != nil {
 		if action, _ := req.Metadata["action"].(string); action == "countTokens" {