fix: use single image for OpenAI SDK images.edit (does not support array)

src/lib/model-gateway/openai-compat/image.ts

@@ -160,10 +160,12 @@ export async function generateImageViaOpenAICompat(request: OpenAICompatImageReq
   const editModelId = providerKey === 'grok2' ? 'grok-imagine-1.0-edit' : normalizedModelId
 
   if (referenceImages.length > 0) {
+    // OpenAI SDK 的 images.edit 只接受单个图片文件，不支持数组
+    // 如果有多张参考图，只使用第一张
     const response = await client.images.edit({
       model: editModelId,
       prompt,
-      image: await Promise.all(referenceImages.map((image, index) => toUploadFile(image, index))),
+      image: await toUploadFile(referenceImages[0], 0),
       response_format: responseFormat,
       ...(outputFormat ? { output_format: outputFormat } : {}),
       ...(quality ? { quality } : {}),