feat: implement advanced analytics for mobile admin dashboard

This commit includes:
- Backend EventAnalyticsService and Controller
- API endpoint for event analytics
- Frontend EventAnalyticsPage with custom bar charts and top contributor lists
- Analytics shortcut on the dashboard
- Feature-lock upsell UI for non-premium users

resources/js/admin/mobile/theme.ts

@@ -29,6 +29,7 @@ export const ADMIN_ACTION_COLORS = {
   photobooth: '#FF8A8E',
   recap: ADMIN_COLORS.warning,
   packages: ADMIN_COLORS.primary,
+  analytics: '#8b5cf6',
 };
 
 export const ADMIN_GRADIENTS = {