The first real settings tab. The Claude extension contributes an Activity SettingsCategory whose fold-level select binds to app.claude.activityFoldLevel; the activity panes already rebuild off the settings notifier, so a pick applies live. Proves the schema-driven engine end to end with a production setting — opening Settings now shows a populated, working category. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>