feat: add description to model interface (#689)

## Problem
We also want to display the model description

## Solution
Add description field

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## License

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under the terms of the Apache 2.0 license.

Author: chungjac

types/chat.ts

@@ -719,6 +719,7 @@ export interface PromptInputOptionChangeParams {
 export interface Model {
     id: string
     name: string
+    description?: string
 }
 
 export interface ListAvailableModelsParams {