Add event list feature (009-list-events)

Enable users to see all their saved events on the home screen, sorted
by date with upcoming events first. Key capabilities:

- EventCard with title, relative time display, and organizer/attendee
  role badge
- Sortable EventList with past-event visual distinction (faded style)
- Empty state when no events are stored
- Swipe-to-delete gesture with confirmation dialog
- Floating action button for quick event creation
- Rename router param :token → :eventToken across all views
- useRelativeTime composable (Intl.RelativeTimeFormat)
- useEventStorage: add validation, removeEvent(), reactive versioning
- Full E2E and unit test coverage for all new components

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

frontend/src/composables/useEventStorage.ts

@@ -8,8 +8,26 @@ export interface StoredEvent {
   rsvpName?: string
 }
 
+import { ref } from 'vue'
+
 const STORAGE_KEY = 'fete:events'
 
+const version = ref(0)
+
+export function isValidStoredEvent(e: unknown): e is StoredEvent {
+  if (typeof e !== 'object' || e === null) return false
+  const obj = e as Record<string, unknown>
+  return (
+    typeof obj.eventToken === 'string' &&
+    obj.eventToken.length > 0 &&
+    typeof obj.title === 'string' &&
+    obj.title.length > 0 &&
+    typeof obj.dateTime === 'string' &&
+    obj.dateTime.length > 0 &&
+    !isNaN(new Date(obj.dateTime).getTime())
+  )
+}
+
 function readEvents(): StoredEvent[] {
   try {
     const raw = localStorage.getItem(STORAGE_KEY)
@@ -21,6 +39,7 @@ function readEvents(): StoredEvent[] {
 
 function writeEvents(events: StoredEvent[]): void {
   localStorage.setItem(STORAGE_KEY, JSON.stringify(events))
+  version.value++
 }
 
 export function useEventStorage() {
@@ -31,6 +50,7 @@ export function useEventStorage() {
   }
 
   function getStoredEvents(): StoredEvent[] {
+    void version.value
     return readEvents()
   }
 
@@ -59,5 +79,10 @@ export function useEventStorage() {
     return undefined
   }
 
-  return { saveCreatedEvent, getStoredEvents, getOrganizerToken, saveRsvp, getRsvp }
+  function removeEvent(eventToken: string): void {
+    const events = readEvents().filter((e) => e.eventToken !== eventToken)
+    writeEvents(events)
+  }
+
+  return { saveCreatedEvent, getStoredEvents, getOrganizerToken, saveRsvp, getRsvp, removeEvent }
 }