content-addressed blob storage: blob_storage.py, memory, local, and S3 adapters

src/kontextual_engine/core/cmis.py

@@ -858,7 +858,9 @@ def _preferred_representation(
         RepresentationKind.NORMALIZED: 1,
         RepresentationKind.DERIVED: 2,
     }
-    return sorted(representations, key=lambda item: priority.get(item.kind, 99))[0]
+    best_priority = min(priority.get(item.kind, 99) for item in representations)
+    candidates = [item for item in representations if priority.get(item.kind, 99) == best_priority]
+    return sorted(candidates, key=lambda item: (item.created_at, item.representation_id), reverse=True)[0]
 
 
 def _normalize_path(path: str) -> str: