Add setting to disable Recent Activity display on startup

Feature Request

When Claude Code starts up, it displays a "Recent activity" section. There is currently no way to disable this.

Requested behavior: Add a setting (e.g., showRecentActivity: false in settings.json) to allow users to hide the Recent Activity display on startup.

Use case: Some users prefer a clean, minimal startup experience and don't need to see recent activity each time they open Claude Code.

Thank you!