Add event stub page with clipboard sharing

Post-creation confirmation page showing shareable event URL with
copy-to-clipboard and fallback feedback on failure.

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

frontend/src/views/__tests__/EventStubView.spec.ts

@@ -0,0 +1,87 @@
+import { describe, it, expect, vi } from 'vitest'
+import { mount } from '@vue/test-utils'
+import { createRouter, createMemoryHistory } from 'vue-router'
+import EventStubView from '../EventStubView.vue'
+
+function createTestRouter() {
+  return createRouter({
+    history: createMemoryHistory(),
+    routes: [
+      { path: '/', name: 'home', component: { template: '<div />' } },
+      { path: '/events/:token', name: 'event', component: EventStubView },
+    ],
+  })
+}
+
+async function mountWithToken(token = 'test-token-123') {
+  const router = createTestRouter()
+  await router.push(`/events/${token}`)
+  await router.isReady()
+  return mount(EventStubView, {
+    global: { plugins: [router] },
+  })
+}
+
+describe('EventStubView', () => {
+  it('renders the event URL based on route param', async () => {
+    const wrapper = await mountWithToken('abc-def')
+
+    const linkText = wrapper.find('.stub__link').text()
+    expect(linkText).toContain('/events/abc-def')
+  })
+
+  it('shows the correct share URL with origin', async () => {
+    const wrapper = await mountWithToken('my-event-token')
+
+    const linkText = wrapper.find('.stub__link').text()
+    expect(linkText).toBe(`${window.location.origin}/events/my-event-token`)
+  })
+
+  it('has a copy button', async () => {
+    const wrapper = await mountWithToken()
+
+    const copyBtn = wrapper.find('.stub__copy')
+    expect(copyBtn.exists()).toBe(true)
+    expect(copyBtn.text()).toBe('Copy')
+  })
+
+  it('copies link to clipboard and shows confirmation', async () => {
+    const writeTextMock = vi.fn().mockResolvedValue(undefined)
+    Object.assign(navigator, {
+      clipboard: { writeText: writeTextMock },
+    })
+
+    const wrapper = await mountWithToken('copy-test')
+
+    await wrapper.find('.stub__copy').trigger('click')
+
+    expect(writeTextMock).toHaveBeenCalledWith(
+      `${window.location.origin}/events/copy-test`,
+    )
+    expect(wrapper.find('.stub__copy').text()).toBe('Copied!')
+  })
+
+  it('shows failure message when clipboard is unavailable', async () => {
+    Object.assign(navigator, {
+      clipboard: { writeText: vi.fn().mockRejectedValue(new Error('Not allowed')) },
+    })
+
+    const wrapper = await mountWithToken('fail-test')
+
+    await wrapper.find('.stub__copy').trigger('click')
+
+    expect(wrapper.find('.stub__copy').text()).toBe('Failed')
+    expect(wrapper.find('.stub__copy').attributes('aria-label')).toBe(
+      'Copy failed — select the link to copy manually',
+    )
+  })
+
+  it('has a back link to home', async () => {
+    const wrapper = await mountWithToken()
+
+    const backLink = wrapper.find('.stub__back')
+    expect(backLink.exists()).toBe(true)
+    expect(backLink.attributes('aria-label')).toBe('Back to home')
+    expect(backLink.attributes('href')).toBe('/')
+  })
+})