docs: add architecture overview section to README

- Clarify that SDK requires a deployed AxonFlow platform
- Add 2-minute architecture video link
- Explain how SDK fits with the control plane

Author: saurabhjain1592

README.md

@@ -6,6 +6,20 @@ Official Java SDK for [AxonFlow](https://getaxonflow.com) - AI Governance Platfo
 [![Maven Central](https://img.shields.io/maven-central/v/com.getaxonflow/axonflow-sdk.svg)](https://search.maven.org/artifact/com.getaxonflow/axonflow-sdk)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](LICENSE)
 
+## How This SDK Fits with AxonFlow
+
+This SDK is a client library for interacting with a running AxonFlow control plane. It is used from application or agent code to send execution context, policies, and requests at runtime.
+
+A deployed AxonFlow platform (self-hosted or cloud) is required for end-to-end AI governance. SDKs alone are not sufficient—the platform and SDKs are designed to be used together.
+
+### Architecture Overview (2 min)
+
+If you're new to AxonFlow, this short video shows how the control plane and SDKs work together in a real production setup:
+
+[![AxonFlow Architecture Overview](https://img.youtube.com/vi/WwQXHKuZhxc/maxresdefault.jpg)](https://youtu.be/WwQXHKuZhxc)
+
+▶️ [Watch on YouTube](https://youtu.be/WwQXHKuZhxc)
+
 ## Requirements
 
 - Java 11 or higher