fix: handle missing popiserver task images

src/app/api/generate/providers/popiserver.ts

@@ -564,7 +564,7 @@ function extractOutputFromTask(task: PopiTask, mediaType: string): GenerationOut
   // payloads. Only use it as a defensive fallback for older responses that do
   // not put generated images under resultList.
   const images = [
-    ...new Set(resultImages.length > 0 ? resultImages : collectStrings(task.images)),
+    ...new Set(resultImages.length > 0 ? resultImages : collectStrings(task.images ?? [])),
   ];
   return images.length > 0
     ? { success: true, outputs: images.map((url) => ({ type: "image", data: "", url })) }