fix: wrap team creation in a transaction, add more-menu entry point, fix lint

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

myteamwallet_backend/src/teams/teams.controller.spec.ts

@@ -31,7 +31,7 @@ describe('TeamsController', () => {
     const req = { user: { id: 42 } };
     const dto = { name: '1. Herren' };
 
-    controller.create(req as any, dto as any);
+    void controller.create(req as any, dto as any);
 
     expect(service.createNewTeam).toHaveBeenCalledWith(dto, 42);
   });