✨ Add theme support

src/store.js

@@ -11,6 +11,7 @@ export const timetableGroups = ref(
   JSON.parse(localStorage.getItem("timetableGroups") || "[]")
 );
 export const language = ref(localStorage.getItem("lang") || "en");
+export const theme = ref(localStorage.getItem("theme") || "auto");
 
 watch(classFilter, (newValue) => {
   localStorage.setItem("classFilter", newValue);
@@ -24,6 +25,9 @@ watch(language, (newValue) => {
   localStorage.setItem("lang", newValue);
   location.reload();
 });
+watch(theme, (newValue) => {
+  localStorage.setItem("theme", newValue);
+});
 
 // Set this to a positive or negative integer
 // to change selectedDate by this number