fix: enable auto_mkdir for local filesystem in StorageBackend

The fsspec local filesystem needs auto_mkdir=True to automatically
create parent directories when writing files. This is required for
Zarr 3.x which doesn't create directories when opening arrays with
mode='w' through an FSMap.

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: dimitri-yatsenko

src/datajoint/storage.py

@@ -287,7 +287,7 @@ def fs(self) -> fsspec.AbstractFileSystem:
     def _create_filesystem(self) -> fsspec.AbstractFileSystem:
         """Create fsspec filesystem based on protocol."""
         if self.protocol == "file":
-            return fsspec.filesystem("file")
+            return fsspec.filesystem("file", auto_mkdir=True)
 
         elif self.protocol == "s3":
             # Build S3 configuration