feat: manage waitlist and remove group members

- Add group-waitlist module (list/promote/remove entries)
- Remove attendee with optional atomic promotion from waitlist
- Block removal when attendee has payments (attendee_has_payments)
- Waitlist detail modal matching members UI; optimistic add-to-waitlist
- Responsive tweaks for the members/waitlist tabs

apps/backend/src/modules/groups/routes.ts

@@ -2,6 +2,8 @@ import { Hono } from 'hono';
 import addToGroupWaitlistRoute from '../attendees/features/add-to-waitlist/route';
 import bulkCreateAttendeesRoute from '../attendees/features/bulk-create/route';
 import createAttendeeRoute from '../attendees/features/create/route';
+import removeAttendeeRoute from '../attendees/features/remove/route';
+import groupWaitlistRoutes from '../group-waitlist/routes';
 import createFromOrganizationRoute from './features/create-from-organization/route';
 import getAllRoute from './features/get-all/route';
 import getByIdRoute from './features/get-by-id/route';
@@ -18,5 +20,7 @@ routes.route('/', createAttendeeRoute);
 routes.route('/', bulkCreateAttendeesRoute);
 routes.route('/', getByIdRoute);
 routes.route('/', addToGroupWaitlistRoute);
+routes.route('/', groupWaitlistRoutes);
+routes.route('/', removeAttendeeRoute);
 
 export default routes;