Implement watch-event feature (017) with bookmark in RsvpBar

Add client-side watch/bookmark functionality: users can save events to
localStorage without RSVPing via a bookmark button next to the "I'm attending"
CTA. Watched events appear in the event list with a "Watching" label.
Bookmark is only visible for visitors (not attendees or organizers).

Includes spec, plan, research, tasks, unit tests, and E2E tests.

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

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

@@ -63,6 +63,12 @@ describe('EventCard', () => {
     expect(wrapper.text()).toContain('Attendee')
   })
 
+  it('renders watcher badge when eventRole is watcher', () => {
+    const wrapper = mountCard({ eventRole: 'watcher' })
+    expect(wrapper.find('.event-card__badge--watcher').exists()).toBe(true)
+    expect(wrapper.text()).toContain('Watching')
+  })
+
   it('renders no badge when eventRole is undefined', () => {
     const wrapper = mountCard({ eventRole: undefined })
     expect(wrapper.find('.event-card__badge').exists()).toBe(false)

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

@@ -20,6 +20,8 @@ const mockEvents = [
   { eventToken: 'today-1', title: 'Today Event', dateTime: '2026-03-11T18:00:00' },
   { eventToken: 'week-1', title: 'This Week Event', dateTime: '2026-03-13T10:00:00' },
   { eventToken: 'nextweek-1', title: 'Next Week Event', dateTime: '2026-03-16T10:00:00' },
+  { eventToken: 'org-1', title: 'Organized Event', dateTime: '2026-03-11T19:00:00', organizerToken: 'org-token' },
+  { eventToken: 'rsvp-1', title: 'Attending Event', dateTime: '2026-03-11T20:00:00', rsvpToken: 'rsvp-token', rsvpName: 'Max' },
 ]
 
 vi.mock('../../composables/useEventStorage', () => ({
@@ -32,6 +34,13 @@ vi.mock('../../composables/useEventStorage', () => ({
   },
   useEventStorage: () => ({
     getStoredEvents: () => mockEvents,
+    getRsvp: (token: string) => {
+      const evt = mockEvents.find((e) => e.eventToken === token)
+      if (evt && 'rsvpToken' in evt && 'rsvpName' in evt) {
+        return { rsvpToken: evt.rsvpToken, rsvpName: evt.rsvpName }
+      }
+      return undefined
+    },
     removeEvent: vi.fn(),
   }),
 }))
@@ -40,7 +49,9 @@ vi.mock('../../composables/useRelativeTime', () => ({
   formatRelativeTime: (dateTime: string) => {
     if (dateTime.includes('03-01')) return '10 days ago'
     if (dateTime.includes('06-15')) return 'in 1 year'
-    if (dateTime.includes('03-11')) return 'in 6 hours'
+    if (dateTime.includes('03-11T18')) return 'in 6 hours'
+    if (dateTime.includes('03-11T19')) return 'in 7 hours'
+    if (dateTime.includes('03-11T20')) return 'in 8 hours'
     if (dateTime.includes('03-13')) return 'in 2 days'
     if (dateTime.includes('03-16')) return 'in 5 days'
     return 'sometime'
@@ -89,7 +100,7 @@ describe('EventList', () => {
   it('renders all valid events as cards', () => {
     const wrapper = mountList()
     const cards = wrapper.findAll('.event-card')
-    expect(cards).toHaveLength(5)
+    expect(cards).toHaveLength(7)
   })
 
   it('marks past events with isPast class', () => {
@@ -137,4 +148,25 @@ describe('EventList', () => {
     const pastSection = wrapper.findAll('.event-section')[4]!
     expect(pastSection.find('.date-subheader').exists()).toBe(true)
   })
+
+  it('assigns watcher role when event has no organizerToken and no rsvpToken', () => {
+    const wrapper = mountList()
+    const badges = wrapper.findAll('.event-card__badge--watcher')
+    expect(badges.length).toBeGreaterThanOrEqual(1)
+    expect(badges[0]!.text()).toBe('Watching')
+  })
+
+  it('assigns organizer role when event has organizerToken', () => {
+    const wrapper = mountList()
+    const badge = wrapper.find('.event-card__badge--organizer')
+    expect(badge.exists()).toBe(true)
+    expect(badge.text()).toBe('Organizer')
+  })
+
+  it('assigns attendee role when event has rsvpToken', () => {
+    const wrapper = mountList()
+    const badge = wrapper.find('.event-card__badge--attendee')
+    expect(badge.exists()).toBe(true)
+    expect(badge.text()).toBe('Attendee')
+  })
 })