✨ Switch to global date selector

src/store.js

@@ -20,6 +20,9 @@ watch(timetableClass, (newValue) => {
   fetchData();
 });
 
+export const selectedDate = ref(new Date(new Date().setUTCHours(0, 0, 0, 0)));
+export const selectedDay = computed(() => selectedDate.value.getDay() - 1);
+
 export const timetable = ref([]);
 export const substitutions = ref([]);
 export const history = ref([]);