Revert "refactor: make the reference week a dense one-row-per-day table"

This reverts commit c8235763b0.

lib/schedule/week.ts

@@ -12,17 +12,6 @@ import { validateSlots } from './validate';
 /** Monday first: how the week is read, and how the screen draws it. */
 export const WEEK_ORDER = [1, 2, 3, 4, 5, 6, 0] as const;
 
-/** Three letters, for the dense week table. */
-export const DAY_SHORT_FR: Record<number, string> = {
-  0: 'Dim',
-  1: 'Lun',
-  2: 'Mar',
-  3: 'Mer',
-  4: 'Jeu',
-  5: 'Ven',
-  6: 'Sam',
-};
-
 export const DAY_NAMES_FR: Record<number, string> = {
   0: 'Dimanche',
   1: 'Lundi',