fix(dashboard): bind Upcoming sidebar to reactive useFetch data

ColumnsLayout mounts inside <ClientOnly> on /member/dashboard, so the
SSR fetch returned the empty default and the snapshot assignment to
upcomingEvents never re-ran after the client-side fetch resolved.

Skip the SSR phase explicitly (server: false) and expose data to the
template via a computed so post-fetch updates propagate to
EventsMiniSidebar.

app/components/ColumnsLayout.vue

@@ -29,13 +29,14 @@ const props = defineProps({
   limit: { type: Number, default: 3 },
 })
 
-const upcomingEvents = ref([])
+let upcomingEvents = ref([])
 if (props.cols === 'events-sidebar') {
   const { data } = await useFetch('/api/events', {
     query: { upcoming: true, limit: props.limit },
     default: () => [],
+    server: false,
   })
-  upcomingEvents.value = data.value || []
+  upcomingEvents = computed(() => data.value || [])
 }
 </script>