feat(events): add Back button to the calendar page

The calendar page had no way back to the feed except the browser/back
gesture. Add a top-bar ghost Back link (ArrowLeft + "Back" → events feed)
mirroring EventDetailPage's pattern for navigation consistency.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/modules/events/views/EventsCalendarPage.vue

@@ -2,7 +2,7 @@
 import { computed, onMounted, ref } from 'vue'
 import { useRouter } from 'vue-router'
 import { useI18n } from 'vue-i18n'
-import { Ticket } from 'lucide-vue-next'
+import { ArrowLeft, Ticket } from 'lucide-vue-next'
 import { Button } from '@/components/ui/button'
 import { useEvents } from '../composables/useEvents'
 import { useOwnedTickets } from '../composables/useOwnedTickets'
@@ -34,10 +34,23 @@ onMounted(() => {
 function handleSelectEvent(event: Event) {
   router.push({ name: 'event-detail', params: { id: event.id } })
 }
+
+function goBack() {
+  router.push({ name: 'events' })
+}
 </script>
 
 <template>
   <div class="container mx-auto px-4 py-6 max-w-lg">
+    <!-- Back to the events feed — mirrors EventDetailPage's top-bar
+         back link for navigation consistency. -->
+    <div class="flex items-center mb-4">
+      <Button variant="ghost" size="sm" class="gap-1.5" @click="goBack">
+        <ArrowLeft class="w-4 h-4" />
+        {{ t('common.nav.back', 'Back') }}
+      </Button>
+    </div>
+
     <!-- Filter chip: narrows the calendar to events the user has
          paid tickets for. Hidden when logged out — nothing to own.
          Left-aligned so it doesn't collide with the fixed top-right