fix: sat display

[AureliaSindhu]

Summary

Fixed the calendar week layout so Saturday appears after Friday instead of before Sunday. Changed the week start day from Saturday (dow: 6) to Sunday (dow: 0).
Before: Sa | Su | M | Tu | W | Th | F
After: Su | M | Tu | W | Th | F | Sa

Test Plan

• Add courses that meet Monday-Friday - verify they appear in the correct columns
• Add a course that meets on Saturday - verify it appears in the rightmost column (after Friday)
• Add a course that meets on Sunday - verify it appears in the leftmost column
• Verify the calendar displays days in order: Su, M, Tu, W, Th, F, Sa

Issues

Saturday was displayed for the intial week.

Closes #1358

[KevinWu098]

This looks like it does work for regular weeks, but on finals weeks, the week begins on Saturday. You can see this on the schedule, Fall 2025 exams are Dec 6–12 (Dec 6 is a Saturday).

In updating the start of the week, we have regressed in this area. Although it's outside the scope of the original issue, we should A. fix this and B. cannot proceed with this PR as it breaks finals functionality (which is more critical than the occasional Saturday class)

Your branch:

Production:

We may be able to dynamically update the start of the week based on if we're in finals viewing mode.