fix(#28): add right arrow to BreakRule step and correct back nav

- BreakRule step now shows a right arrow that advances using current selection
- Back navigation from BreakRule returns to Race To instead of exiting to list

Refs #28

src/components/screens/NewGameScreen.tsx

@@ -84,6 +84,9 @@ export default function NewGameScreen({
       case 'raceTo':
         onStepChange('gameType');
         break;
+      case 'breakRule':
+        onStepChange('raceTo');
+        break;
       case 'breakOrder':
         onStepChange('breakRule');
         break;