fix(events): inline-arrow multi-statement @update:open handler

Vue's template expression parser doesn't accept multi-line statement
bodies separated by newlines alone — it errors with 'Unexpected token,
expected ","' as it tries to parse the second statement as a
continuation of the first. Convert to the inline-arrow form already
used elsewhere in the codebase (WalletPage.vue, TaskCard.vue, etc.).

src/modules/activities/views/EventsPage.vue

@@ -258,10 +258,7 @@ function handleEventChanged() {
       :auto-approve="autoApprove"
       :on-create-event="handleCreateEvent"
       :on-update-event="handleUpdateEvent"
-      @update:open="
-        showEventDialog = $event
-        handleDialogClosed()
-      "
+      @update:open="(open) => { showEventDialog = open; handleDialogClosed() }"
       @event-created="handleEventChanged"
       @event-updated="handleEventChanged"
     />