docs: add Iris stage display changelog entry

Author: Predixx

CHANGELOG.md

@@ -11,6 +11,7 @@ All notable changes to the Artemis VS Code extension will be documented in this
 - **Configurable Start Page**: New `artemis.startPage` setting to choose which page opens after login: Dashboard (default), Course List, or automatically open the course/exercise detected in the current workspace.
 - **Workspace Exercise Detection Prompt**: When an exercise is detected in the workspace, a notification offers to set it as the default start page with a single click. The setting can be changed later in VS Code Settings.
 - **Server URL Dropdown**: Predefined Artemis server URLs in the login dropdown with collapsible exercise header.
+- **Iris Stage Display**: Shows the current Iris processing stage (e.g., thinking, fetching context) in the chat via WebSocket STATUS messages.
 
 ### Changed