New Module Management UI

ESP-Website administrators currently manage program modules manually with no way to pre-schedule transitions, causing configuration errors that risk corrupting student registration data. This project builds a visual, Gantt-style Module Management UI that lets administrators schedule module open/close windows on a drag-and-drop timeline canvas, with separate student and teacher views, real-time conflict detection, and a time scrubber to preview the student experience at any point. On the backend, ProgramModuleObj will be subclassed from ExpirableModel to add native time-windowing, and five AJAX endpoints will power all frontend interactions. Deliverables include the model migration, time-aware module filtering, the timeline canvas UI, a module picker side panel, full WCAG 2.1 AA accessibility, and bidirectional integration with the existing module questions interface.