Fix Copilot SDK session event handler compile issue

[jongalloway]

Summary

• Updates the Copilot SDK PR visualization recipe to subscribe with session.On<SessionEvent>(...).
• Fixes a compile issue caused by the SDK breaking change that now requires the event type for this handler.
• Supersedes Revert Copilot SDK model/session event update #2054, which was opened with an incorrect revert-focused title/base for this fix.

Testing

• Not run. This recipe invokes live Copilot/GitHub tooling, so I kept validation to the focused one-line diff.

[Copilot]

Pull request overview

Updates the .NET Copilot SDK PR visualization runnable recipe to match a breaking change in the SDK’s session event subscription API, restoring compile-time compatibility for the example.

Changes:

• Updates the PR visualization recipe’s session event handler subscription to explicitly specify the event type (session.On<SessionEvent>(...)).

Show a summary per file

File	Description
cookbook/copilot-sdk/dotnet/recipe/pr-visualization.cs	Adjusts the session event subscription to use the SDK’s typed On<TEvent> handler form to address the compile issue.

Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 0