Event search (Ctrl+F), locale/RTL handling, weekday selector workday/weekend, refactored event handling, Firefox compatibility (#3)

Major refactoring for cleanup, with various bugfixes.

Weekday selector in Settings now shows workdays/weekend bars based on current locale (also used to choose default values). Weekday selector in event dialog uses the days set in settings, as expected.

src/components/HeaderControls.vue

@@ -31,7 +31,6 @@
       >
         ⚙
       </button>
-      <!-- Settings dialog now lives here -->
       <SettingsDialog ref="settingsDialog" />
     </div>
   </Transition>
@@ -101,12 +100,12 @@ onBeforeUnmount(() => {
   display: flex;
   justify-content: end;
   align-items: center;
-  margin-right: 1.5rem;
+  margin-inline-end: 2rem;
 }
 .toggle-btn {
   position: fixed;
   top: 0;
-  right: 0;
+  inset-inline-end: 0;
   background: transparent;
   border: none;
   color: var(--muted);
@@ -157,7 +156,6 @@ onBeforeUnmount(() => {
   color: var(--muted);
   padding: 0;
   margin: 0;
-  margin-right: 0.6rem;
   cursor: pointer;
   font-size: 1.5rem;
   line-height: 1;
@@ -205,6 +203,6 @@ onBeforeUnmount(() => {
 .today-date {
   white-space: pre-line;
   text-align: center;
-  margin-right: 2rem;
+  margin-inline-end: 2rem;
 }
 </style>