Add comment explaining why _BatchContext Protocol exists

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Abel Milash

src/PowerPlatform/Dataverse/operations/batch.py

@@ -67,9 +67,15 @@
 class _BatchContext(Protocol):
     """Structural interface required by batch operation namespaces.
 
+    The operation namespaces (BatchRecordOperations, BatchTableOperations, etc.)
+    accept a ``_BatchContext`` rather than a concrete ``BatchRequest`` or
+    ``AsyncBatchRequest``, so that the same namespace classes can be reused by
+    both the sync and async batch implementations without importing either
+    concrete class — avoiding a circular dependency.
+
     Both :class:`~PowerPlatform.Dataverse.operations.batch.BatchRequest` and
     :class:`~PowerPlatform.Dataverse.aio.operations.async_batch.AsyncBatchRequest`
-    satisfy this protocol — no explicit inheritance needed on either class.
+    satisfy this protocol structurally — no explicit inheritance needed.
     """
 
     _items: List[Any]