feat: add class discounts, frontend visibility, and public listing

Add hasDiscount, freeSpots, and showOnFrontend on classes with a public get-all endpoint and richer notification user populate.

components/classes/classRoutes.js

@@ -9,6 +9,9 @@ const { PERMISSIONS } = require('../../constants/permissions');
 
 const router = express.Router();
 
+// Public Scope
+router.get('/user/get-all', classController.getPublicClasses);
+
 router.use(authMiddleware);
 
 // User Scope