Add canonical chunk plan source model

internal/framework/pipeline/runner.go

@@ -863,6 +863,8 @@ func cloneSourceChunk(chunk source.Chunk) source.Chunk {
 	chunk.Content = append([]byte(nil), chunk.Content...)
 	chunk.Units = cloneSourceUnits(chunk.Units)
 	chunk.Metadata = cloneMetadata(chunk.Metadata)
+	chunk.Annotations = source.CloneChunkAnnotations(chunk.Annotations)
+	chunk.PlanAnnotations = source.CloneChunkAnnotations(chunk.PlanAnnotations)
 	return chunk
 }