fix(app): replace Vuetify 2 legacy props with proper V3 API

Replace deprecated V2 props that were being silently ignored:
- v-layout → v-row, grid-list-md removed, xs → cols on v-col
- v-tooltip top → location="top", v-list dense → density="compact"
- v-app-bar app/scroll-off-screen → scroll-behavior="hide"
- append-outer-icon → append-icon, remove primary-title
- headline class → text-h6, remove wrap from v-row

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/components/pages/events/event-list.vue

@@ -1,7 +1,7 @@
 <template>
   <div>
-    <v-row v-for="event in events" :key="event.id" wrap>
-      <v-col xs="12">
+    <v-row v-for="event in events" :key="event.id">
+      <v-col cols="12">
         <event-card
           :event="event"
           :has-user="hasUser"