Implement event creation frontend (EventCreateView)

Form with client-side validation, server error handling, aria-invalid/
aria-describedby for a11y, localStorage persistence via useEventStorage
composable. Routes for /create and /events/:token.

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

frontend/src/composables/__tests__/useEventStorage.spec.ts

@@ -0,0 +1,119 @@
+import { describe, it, expect, beforeEach } from 'vitest'
+import { useEventStorage } from '../useEventStorage'
+
+// jsdom provides a working localStorage in the window object
+// but Node's --localstorage-file warning can be ignored
+function clearStorage() {
+  try {
+    window.localStorage.setItem('fete:events', '[]')
+  } catch {
+    // Provide a minimal mock if localStorage is broken
+    const store: Record<string, string> = {}
+    Object.defineProperty(globalThis, 'localStorage', {
+      value: {
+        getItem: (key: string) => store[key] ?? null,
+        setItem: (key: string, val: string) => {
+          store[key] = val
+        },
+        removeItem: (key: string) => {
+          delete store[key]
+        },
+      },
+      writable: true,
+      configurable: true,
+    })
+  }
+}
+
+describe('useEventStorage', () => {
+  beforeEach(() => {
+    clearStorage()
+  })
+
+  it('returns empty array when no events stored', () => {
+    const { getStoredEvents } = useEventStorage()
+    expect(getStoredEvents()).toEqual([])
+  })
+
+  it('saves and retrieves a created event', () => {
+    const { saveCreatedEvent, getStoredEvents } = useEventStorage()
+
+    saveCreatedEvent({
+      eventToken: 'abc-123',
+      organizerToken: 'org-456',
+      title: 'Birthday',
+      dateTime: '2026-06-15T20:00:00+02:00',
+      expiryDate: '2026-07-15',
+    })
+
+    const events = getStoredEvents()
+    expect(events).toHaveLength(1)
+    expect(events[0]!.eventToken).toBe('abc-123')
+    expect(events[0]!.organizerToken).toBe('org-456')
+    expect(events[0]!.title).toBe('Birthday')
+  })
+
+  it('returns organizer token for known event', () => {
+    const { saveCreatedEvent, getOrganizerToken } = useEventStorage()
+
+    saveCreatedEvent({
+      eventToken: 'abc-123',
+      organizerToken: 'org-456',
+      title: 'Test',
+      dateTime: '2026-06-15T20:00:00+02:00',
+      expiryDate: '2026-07-15',
+    })
+
+    expect(getOrganizerToken('abc-123')).toBe('org-456')
+  })
+
+  it('returns undefined organizer token for unknown event', () => {
+    const { getOrganizerToken } = useEventStorage()
+    expect(getOrganizerToken('unknown')).toBeUndefined()
+  })
+
+  it('stores multiple events independently', () => {
+    const { saveCreatedEvent, getStoredEvents } = useEventStorage()
+
+    saveCreatedEvent({
+      eventToken: 'event-1',
+      title: 'First',
+      dateTime: '2026-06-15T20:00:00+02:00',
+      expiryDate: '2026-07-15',
+    })
+
+    saveCreatedEvent({
+      eventToken: 'event-2',
+      title: 'Second',
+      dateTime: '2026-07-15T20:00:00+02:00',
+      expiryDate: '2026-08-15',
+    })
+
+    const events = getStoredEvents()
+    expect(events).toHaveLength(2)
+    expect(events.map((e) => e.eventToken)).toContain('event-1')
+    expect(events.map((e) => e.eventToken)).toContain('event-2')
+  })
+
+  it('overwrites event with same token', () => {
+    const { saveCreatedEvent, getStoredEvents } = useEventStorage()
+
+    saveCreatedEvent({
+      eventToken: 'abc-123',
+      title: 'Old Title',
+      dateTime: '2026-06-15T20:00:00+02:00',
+      expiryDate: '2026-07-15',
+    })
+
+    saveCreatedEvent({
+      eventToken: 'abc-123',
+      title: 'New Title',
+      dateTime: '2026-06-15T20:00:00+02:00',
+      expiryDate: '2026-07-15',
+    })
+
+    const events = getStoredEvents()
+    expect(events).toHaveLength(1)
+    expect(events[0]!.title).toBe('New Title')
+  })
+})

frontend/src/composables/useEventStorage.ts

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+export interface StoredEvent {
+  eventToken: string
+  organizerToken?: string
+  title: string
+  dateTime: string
+  expiryDate: string
+}
+
+const STORAGE_KEY = 'fete:events'
+
+function readEvents(): StoredEvent[] {
+  try {
+    const raw = localStorage.getItem(STORAGE_KEY)
+    return raw ? (JSON.parse(raw) as StoredEvent[]) : []
+  } catch {
+    return []
+  }
+}
+
+function writeEvents(events: StoredEvent[]): void {
+  localStorage.setItem(STORAGE_KEY, JSON.stringify(events))
+}
+
+export function useEventStorage() {
+  function saveCreatedEvent(event: StoredEvent): void {
+    const events = readEvents().filter((e) => e.eventToken !== event.eventToken)
+    events.push(event)
+    writeEvents(events)
+  }
+
+  function getStoredEvents(): StoredEvent[] {
+    return readEvents()
+  }
+
+  function getOrganizerToken(eventToken: string): string | undefined {
+    const event = readEvents().find((e) => e.eventToken === eventToken)
+    return event?.organizerToken
+  }
+
+  return { saveCreatedEvent, getStoredEvents, getOrganizerToken }
+}