clarify rbac-limited access instead of full kubernetes api access

Author: sarthyparty

docs/architecture/README.md

@@ -67,7 +67,7 @@ NGF implements Kubernetes Gateway API resources. For supported resources and the
 
 ### Control Plane Security
 
-- **Full Kubernetes API access** (to watch resources)
+- **Limited Kubernetes API access** (RBAC-controlled permissions to watch resources)
 - **gRPC server** for data plane connections
 - **Certificate management** for secure communication