docs: Add alpha and beta labels for respective LangGraph Platform deployment options (#4249)

### Summary
Examples:

![image](https://github.com/user-attachments/assets/2a36a262-5373-498d-9907-19d5447fbb6a)


![image](https://github.com/user-attachments/assets/70671e08-34b6-40ed-964d-9d195ea8308d)


![image](https://github.com/user-attachments/assets/fcb877a6-475c-47a4-b8af-91cbdc00f89b)

docs/docs/cloud/deployment/cloud.md

@@ -1,4 +1,4 @@
-# How to Deploy to Cloud SaaS
+# How to Deploy to Cloud SaaS (Beta)
 
 Before deploying, review the [conceptual guide for the Cloud SaaS](../../concepts/langgraph_cloud.md) deployment option.
 

docs/docs/cloud/deployment/self_hosted_control_plane.md

@@ -1,4 +1,4 @@
-# How to Deploy Self-Hosted Control Plane
+# How to Deploy Self-Hosted Control Plane (Beta)
 
 Before deploying, review the [conceptual guide for the Self-Hosted Control Plane](../../concepts/langgraph_self_hosted_control_plane.md) deployment option.
 

docs/docs/cloud/deployment/self_hosted_data_plane.md

@@ -1,4 +1,4 @@
-# How to Deploy Self-Hosted Data Plane
+# How to Deploy Self-Hosted Data Plane (Beta)
 
 Before deploying, review the [conceptual guide for the Self-Hosted Data Plane](../../concepts/langgraph_self_hosted_data_plane.md) deployment option.