Add organizer-only attendee list to event detail view (011)

New GET /events/{token}/attendees endpoint returns attendee names when
a valid organizer token is provided (403 otherwise). The frontend
conditionally renders the list below the attendee count for organizers,
silently degrading for visitors.

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

frontend/src/components/AttendeeList.vue

@@ -0,0 +1,59 @@
+<template>
+  <section class="attendee-list">
+    <h3 class="attendee-list__heading">
+      {{ attendees.length === 1 ? '1 Attendee' : `${attendees.length} Attendees` }}
+    </h3>
+    <ul v-if="attendees.length > 0" class="attendee-list__items">
+      <li v-for="(name, index) in attendees" :key="index" class="attendee-list__item">
+        {{ name }}
+      </li>
+    </ul>
+    <p v-else class="attendee-list__empty">No attendees yet.</p>
+  </section>
+</template>
+
+<script setup lang="ts">
+defineProps<{
+  attendees: string[]
+}>()
+</script>
+
+<style scoped>
+.attendee-list {
+  display: flex;
+  flex-direction: column;
+  gap: var(--spacing-sm);
+}
+
+.attendee-list__heading {
+  font-size: 0.75rem;
+  font-weight: 700;
+  color: rgba(255, 255, 255, 0.5);
+  text-transform: uppercase;
+  letter-spacing: 0.08em;
+}
+
+.attendee-list__items {
+  list-style: none;
+  padding: 0;
+  margin: 0;
+  display: flex;
+  flex-direction: column;
+  gap: var(--spacing-xs);
+}
+
+.attendee-list__item {
+  font-size: 0.95rem;
+  color: rgba(255, 255, 255, 0.85);
+  line-height: 1.4;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.attendee-list__empty {
+  font-size: 0.9rem;
+  color: rgba(255, 255, 255, 0.5);
+  font-style: italic;
+}
+</style>

frontend/src/components/__tests__/AttendeeList.spec.ts

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+import { describe, it, expect } from 'vitest'
+import { mount } from '@vue/test-utils'
+import AttendeeList from '../AttendeeList.vue'
+
+describe('AttendeeList', () => {
+  it('renders attendee names as list items', () => {
+    const wrapper = mount(AttendeeList, {
+      props: { attendees: ['Alice', 'Bob', 'Charlie'] },
+    })
+
+    const items = wrapper.findAll('.attendee-list__item')
+    expect(items).toHaveLength(3)
+    expect(items[0]!.text()).toBe('Alice')
+    expect(items[1]!.text()).toBe('Bob')
+    expect(items[2]!.text()).toBe('Charlie')
+  })
+
+  it('shows empty state message when no attendees', () => {
+    const wrapper = mount(AttendeeList, {
+      props: { attendees: [] },
+    })
+
+    expect(wrapper.find('.attendee-list__empty').text()).toBe('No attendees yet.')
+    expect(wrapper.find('.attendee-list__items').exists()).toBe(false)
+  })
+
+  it('shows plural count heading for multiple attendees', () => {
+    const wrapper = mount(AttendeeList, {
+      props: { attendees: ['Alice', 'Bob', 'Charlie', 'Diana', 'Eve'] },
+    })
+
+    expect(wrapper.find('.attendee-list__heading').text()).toBe('5 Attendees')
+  })
+
+  it('shows singular count heading for one attendee', () => {
+    const wrapper = mount(AttendeeList, {
+      props: { attendees: ['Alice'] },
+    })
+
+    expect(wrapper.find('.attendee-list__heading').text()).toBe('1 Attendee')
+  })
+
+  it('shows zero count heading for no attendees', () => {
+    const wrapper = mount(AttendeeList, {
+      props: { attendees: [] },
+    })
+
+    expect(wrapper.find('.attendee-list__heading').text()).toBe('0 Attendees')
+  })
+})