feat: optimize app by reducing rerenders

[KevinWu098]

Summary

Using react-scan, we can identify areas with high rerenders and optimize AntAlmanac's performance. This PR targets three areas:

• Refactors and cleans up SectionTableBody and HoveredStore to remove unnecessary rerenders when hovering courses
• Refactors and cleans up CalendarRoot to stop rerenders when interacting with calendar event elements
• Refactors and cleans up SectionTableBody and adding courses, to remove renders caused by adding courses

Before

SectionTableBody (hovering)

Calendar

SectionTableBody (adding courses)

After

SectionTableBody (hovering)

Note: the key thing is that SectionTableBody now does not rerender rows -- the calendar is expected to rerender (although it would be preferable if the entire thing didn't rerender, but that's a library level problem)

Calendar

SectionTableBody (adding courses)

Test Plan

1. Interact with Calendar events. Click, click out. Elements should behave as before (clicking an event triggers a Popover)
2. Repeat # 1 on mobile screen sizes
3. With Hover to Preview courses on and off, search and interact with both the Search and the Added panes. There should be no rerenders of rows on hover.
4. Add courses to your schedule. ScheduleConflict (the darker highlighting of courses when it would overlight another course) should update correctly. The yellow highlighting should also update correctly. There should be no rerenders except for courses which overlap the newly added course.

Note: React Scan should only be added to our dev environments (this includes staging), but it should not be added to prod

[MinhxNguyen7]

A few minor gripes

[MinhxNguyen7]

Seems alright