create a new page /tasks for users to see a list of their tasks.
write an api on /api/read/tasks which returns the tasks assigned to the current logged in user's team
fetch the data from the above api and render a to-do list on /tasks page (task name, description, status -> checkbox) which can be viewed by the team members but the list can be ticked as 'completed' only by the team lead
once the lead marks a task as completed, add the particular task's score to their team' score
do not allow further modifications
further dev scope: there's a possibility of lead fake marking the task for more points, a confirmation popup can be developed which would prompt the lead before he marks task as completed. the prompt can ask the lead to upload a screenshot of task completion or the url of problem submission or [add your brain's creativity to solve this]