refactor: wrap checkpoint_ns in to_storage_safe_str when building the query

Co-authored-by: Copilot <[email protected]>

Author: bsbodden

langgraph/checkpoint/redis/base.py

@@ -506,7 +506,7 @@ def _load_pending_writes(
         # because RediSearch may not handle sentinel values correctly in tag fields
         writes_query = FilterQuery(
             filter_expression=(Tag("thread_id") == to_storage_safe_id(thread_id))
-            & (Tag("checkpoint_ns") == checkpoint_ns)
+            & (Tag("checkpoint_ns") == to_storage_safe_str(checkpoint_ns))
             & (Tag("checkpoint_id") == to_storage_safe_id(checkpoint_id)),
             return_fields=["task_id", "idx", "channel", "type", "$.blob"],
             num_results=1000,  # Adjust as needed