Return raw array from fused-pipeline fallback

Downstream code expects arrays with .flags attribute, not GPUFrame.
Extract the underlying gpu/cpu array before returning.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sexp_effects/primitive_libs/streaming_gpu.py

@@ -929,6 +929,9 @@ def prim_fused_pipeline(img, effects_list, **dynamic_params):
                 result = gpu_contrast(result, factor, 0)
             elif op == 'invert':
                 result = gpu_invert(result)
+        # Return raw array, not GPUFrame (downstream expects arrays with .flags attribute)
+        if isinstance(result, GPUFrame):
+            return result.gpu if result.is_on_gpu else result.cpu
         return result
 
     # Get image dimensions