AI-59: Mark LangSmith plugin as experimental (#1441)

Add experimental warnings to the LangSmith plugin, consistent with
the pattern used by OpenTelemetry, Google ADK, and AWS S3 contrib
plugins. Adds RST `.. warning::` blocks to public API class docstrings
and an experimental banner to the README.

Author: xumaple

temporalio/contrib/langsmith/README.md

@@ -1,5 +1,7 @@
 # LangSmith Plugin for Temporal Python SDK
 
+> ⚠️ **This package is currently at an experimental release stage.** ⚠️
+
 This Temporal [Plugin](https://docs.temporal.io/develop/plugins-guide) allows your [LangSmith](https://smith.langchain.com/) traces to work within Temporal Workflows. It propagates trace context across Worker boundaries so that `@traceable` calls, LLM invocations, and Temporal operations show up in a single connected trace, and ensures that replaying does not generate duplicate traces.
 
 ## Quick Start

temporalio/contrib/langsmith/__init__.py

@@ -1,5 +1,9 @@
 """LangSmith integration for Temporal SDK.
 
+.. warning::
+    This package is experimental and may change in future versions.
+    Use with caution in production environments.
+
 This package provides LangSmith tracing integration for Temporal workflows,
 activities, and other operations. It includes automatic run creation and
 context propagation for distributed tracing in LangSmith.

temporalio/contrib/langsmith/_interceptor.py

@@ -533,6 +533,10 @@ class LangSmithInterceptor(
 ):
     """Interceptor that supports client and worker LangSmith run creation
     and context propagation.
+
+    .. warning::
+        This class is experimental and may change in future versions.
+        Use with caution in production environments.
     """
 
     def __init__(

temporalio/contrib/langsmith/_plugin.py

@@ -18,6 +18,10 @@
 class LangSmithPlugin(SimplePlugin):
     """LangSmith tracing plugin for Temporal SDK.
 
+    .. warning::
+        This class is experimental and may change in future versions.
+        Use with caution in production environments.
+
     Provides automatic LangSmith run creation for workflows, activities,
     and other Temporal operations with context propagation.
     """