[Rewrite-Frontend]: Adding clear/undo/redo

In the rewrite version of Notangles, these three buttons: clear/undo/redo are currently disabled becasue the related logics have not been implemented.

For the implementation, we should store an array of actions in the frontend, and maintain this data structure when clicking undo/redo. For the clear functionality, we can call a backend API.

The main logic should be implemented in [this file](https://github.com/devsoc-unsw/notangles/blob/frontend-react-query/client/src/components/planner/timetableTabs/TimetableTabContextMenu.tsx#L92).

Start in client/src/components/planner/timetableTabs/TimetableTabContextMenu.tsx around the linked section, then trace the rewrite frontend's timetable action state and the backend API used for clearing. Confirm how actions are represented and how the clear request is made. Done means clear, undo, and redo are enabled and maintain the expected action history, with clear invoking the backend API.

Written by the indexing model from the issue text.