Update release notes for v1.103

Author: bamurtaugh

release-notes/v1_103.md

@@ -452,10 +452,14 @@ We've simplified the button bar in the pull request description header. The copy
 
 #### Show coding agent PRs in chat
 
+**Setting**: `setting(githubPullRequests.codingAgent.uiIntegration)`
+
 When you start a coding agent session (via `#copilotCodingAgent` or with the **Delegate to coding agent** action), the pull request is rendered as a card in the Chat view.
 
 ![Screenshot of a coding agent PR card in the Chat view.](images/1_103/pr-card-in-chat.png)
 
+Enable the `setting(githubPullRequests.codingAgent.uiIntegration)` setting to enable the new **Delegate to coding agent** button in the Chat view, for repositories that have the agent enabled.
+
 #### Chat sessions (Experimental)
 
 ##### Coding agent chats