Feature request: show changelog link in update/relaunch notification

Summary

When Claude Code detects a new version and prompts the user to relaunch, it would be helpful to include a link to the changelog so users can see what's new before relaunching.

Expected behavior

The update notification includes a "What's new" or "View changelog" link that opens the release notes / changelog for the new version.

Current behavior

The relaunch prompt shows that an update is available but provides no information about what changed in the new version.

Use case

Users may want to know what's in an update before deciding to relaunch — especially mid-session. A changelog link lets them make an informed decision without having to go find release notes manually.