feat: add EventDetail with edit form, occurrence grid, split

src/App.vue

@@ -3,6 +3,7 @@ import { useCalendar } from './composables/useCalendar.js'
 import DropZone from './components/DropZone.vue'
 import HeaderBar from './components/HeaderBar.vue'
 import EventList from './components/EventList.vue'
+import EventDetail from './components/EventDetail.vue'
 
 const { isLoaded } = useCalendar()
 </script>
@@ -18,7 +19,7 @@ const { isLoaded } = useCalendar()
       <template v-else>
         <EventList />
         <div class="detail-area">
-          <div class="empty">从左侧选择一个日程进行编辑</div>
+          <EventDetail />
         </div>
       </template>
     </main>