feat: add diagram

Signed-off-by: SuZhou-Joe <[email protected]>

server/README.md

@@ -2,6 +2,8 @@
 
 **Interaction** refers to a question-answer pair in Chatbot application. In most cases, an interaction consists of two messages: an `Input` message and an `Output` message. However, as the Chatbot evolves to become more powerful, it may display new messages such as visualizations, data explorers, or data grids. Therefore, it is crucial to implement a mechanism that allows other plugins to register their customized parser logic based on each interaction body.
 
+![message parser](https://github.com/opensearch-project/dashboards-assistant/assets/13493605/b4ec1ff8-5339-4119-ad20-b2c31057bb0b)
+
 
 ## API