feat: update references to use unified stores configuration

- Update hash_registry.py to use get_store_spec() instead of get_object_store_spec()
- Update staged_insert.py to use get_store_spec() for default store
- Update error messages to reference new stores configuration
- Remove references to object_storage.default_store (now stores.default)

Author: dimitri-yatsenko

src/datajoint/hash_registry.py

@@ -138,20 +138,15 @@ def get_store_backend(store_name: str | None = None) -> StorageBackend:
     Parameters
     ----------
     store_name : str, optional
-        Name of the store to use. If None, uses the default object storage
-        configuration or the configured default_store.
+        Name of the store to use. If None, uses stores.default.
 
     Returns
     -------
     StorageBackend
         StorageBackend instance.
     """
-    # If store_name is None, check for configured default_store
-    if store_name is None and config.object_storage.default_store:
-        store_name = config.object_storage.default_store
-
-    # get_object_store_spec handles None by returning default object_storage config
-    spec = config.get_object_store_spec(store_name)
+    # get_store_spec handles None by using stores.default
+    spec = config.get_store_spec(store_name)
     return StorageBackend(spec)
 
 
@@ -162,14 +157,14 @@ def get_store_subfolding(store_name: str | None = None) -> tuple[int, ...] | Non
     Parameters
     ----------
     store_name : str, optional
-        Name of the store. If None, uses default store.
+        Name of the store. If None, uses stores.default.
 
     Returns
     -------
     tuple[int, ...] | None
         Subfolding pattern (e.g., (2, 2)) or None for flat storage.
     """
-    spec = config.get_object_store_spec(store_name)
+    spec = config.get_store_spec(store_name)
     subfolding = spec.get("subfolding")
     if subfolding is not None:
         return tuple(subfolding)

src/datajoint/staged_insert.py

@@ -69,12 +69,11 @@ def _ensure_backend(self):
         """Ensure storage backend is initialized."""
         if self._backend is None:
             try:
-                spec = config.get_object_storage_spec()
+                spec = config.get_store_spec()  # Uses stores.default
                 self._backend = StorageBackend(spec)
             except DataJointError:
                 raise DataJointError(
-                    "Object storage is not configured. Set object_storage settings in datajoint.json "
-                    "or DJ_OBJECT_STORAGE_* environment variables."
+                    "Storage is not configured. Set stores.default and stores.<name> settings in datajoint.json."
                 )
 
     def _get_storage_path(self, field: str, ext: str = "") -> str:
@@ -110,8 +109,8 @@ def _get_storage_path(self, field: str, ext: str = "") -> str:
                 f"Missing: {set(self._table.primary_key) - set(primary_key)}"
             )
 
-        # Get storage spec
-        spec = config.get_object_storage_spec()
+        # Get storage spec (uses stores.default)
+        spec = config.get_store_spec()
         partition_pattern = spec.get("partition_pattern")
         token_length = spec.get("token_length", 8)