refactor(dataset): split LeRobotDataset into DatasetReader & DatasetWriter (+ API cleanup) (#3180)

* refactor(dataset): split reader and writer

* chore(dataset): remove proxys

* refactor(dataset): better reader & writer encapsulation

* refactor(datasets): clean API + reduce leaky implementations

* refactor(dataset): API cleaning for writer, reader and meta

* refactor(dataset): expose writer & reader + other minor improvements

* refactor(dataset): improve teardown routine

* refactor(dataset): add hf_dataset property at the facade level

* chore(dataset): add init for datasset module

* docs(dataset): add docstrings for public API of the dataset classes

* tests(dataset): add tests for new classes

* fix(dataset): remove circular dependecy

src/lerobot/datasets/image_writer.py

@@ -32,10 +32,10 @@ def safe_stop_image_writer(func):
             return func(*args, **kwargs)
         except Exception as e:
             dataset = kwargs.get("dataset")
-            image_writer = getattr(dataset, "image_writer", None) if dataset else None
-            if image_writer is not None:
+            writer = getattr(dataset, "writer", None) if dataset else None
+            if writer is not None and writer.image_writer is not None:
                 logger.warning("Waiting for image writer to terminate...")
-                image_writer.stop()
+                writer.image_writer.stop()
             raise e
 
     return wrapper