Make expiryDate an internal concern, auto-set to event date + 7 days

The expiry date is no longer user-facing: it is removed from the API
(request and response) and the frontend. The backend now automatically
calculates it as the event date plus 7 days. The expired banner and
RSVP-bar filtering by expired status are also removed from the UI,
since expiry is purely an internal data-retention mechanism.

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

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

@@ -44,7 +44,6 @@ describe('EventCreateView', () => {
     expect(wrapper.find('#description').exists()).toBe(true)
     expect(wrapper.find('#dateTime').exists()).toBe(true)
     expect(wrapper.find('#location').exists()).toBe(true)
-    expect(wrapper.find('#expiryDate').exists()).toBe(true)
   })
 
   it('has required attribute on required fields', async () => {
@@ -58,7 +57,6 @@ describe('EventCreateView', () => {
 
     expect(wrapper.find('#title').attributes('required')).toBeDefined()
     expect(wrapper.find('#dateTime').attributes('required')).toBeDefined()
-    expect(wrapper.find('#expiryDate').attributes('required')).toBeDefined()
   })
 
   it('does not have required attribute on optional fields', async () => {
@@ -102,7 +100,6 @@ describe('EventCreateView', () => {
     // Fill required fields
     await wrapper.find('#title').setValue('My Event')
     await wrapper.find('#dateTime').setValue('2026-12-25T18:00')
-    await wrapper.find('#expiryDate').setValue('2026-12-24')
 
     await wrapper.find('form').trigger('submit')
     await flushPromises()
@@ -127,7 +124,7 @@ describe('EventCreateView', () => {
     await wrapper.find('form').trigger('submit')
 
     const errorsBefore = wrapper.findAll('[role="alert"]').map((el) => el.text()).filter((t) => t.length > 0)
-    expect(errorsBefore.length).toBeGreaterThanOrEqual(3)
+    expect(errorsBefore.length).toBeGreaterThanOrEqual(2)
 
     // Type into title field
     await wrapper.find('#title').setValue('My Event')
@@ -138,9 +135,6 @@ describe('EventCreateView', () => {
 
     const dateTimeError = wrapper.find('#dateTime').element.closest('.form-group')!.querySelector('[role="alert"]')!
     expect(dateTimeError.textContent).not.toBe('')
-
-    const expiryError = wrapper.find('#expiryDate').element.closest('.form-group')!.querySelector('[role="alert"]')!
-    expect(expiryError.textContent).not.toBe('')
   })
 
   it('shows validation errors when submitting empty form', async () => {
@@ -156,7 +150,7 @@ describe('EventCreateView', () => {
 
     const errorElements = wrapper.findAll('[role="alert"]')
     const errorTexts = errorElements.map((el) => el.text()).filter((t) => t.length > 0)
-    expect(errorTexts.length).toBeGreaterThanOrEqual(3)
+    expect(errorTexts.length).toBeGreaterThanOrEqual(2)
   })
 
   it('submits successfully, saves to storage, and navigates to event page', async () => {
@@ -179,7 +173,6 @@ describe('EventCreateView', () => {
         title: 'Birthday Party',
         dateTime: '2026-12-25T18:00:00+01:00',
         timezone: 'Europe/Berlin',
-        expiryDate: '2026-12-24',
       },
       error: undefined,
       response: new Response(),
@@ -198,7 +191,6 @@ describe('EventCreateView', () => {
     await wrapper.find('#description').setValue('Come celebrate!')
     await wrapper.find('#dateTime').setValue('2026-12-25T18:00')
     await wrapper.find('#location').setValue('Berlin')
-    await wrapper.find('#expiryDate').setValue('2026-12-24')
 
     await wrapper.find('form').trigger('submit')
     await flushPromises()
@@ -208,7 +200,6 @@ describe('EventCreateView', () => {
         title: 'Birthday Party',
         description: 'Come celebrate!',
         location: 'Berlin',
-        expiryDate: '2026-12-24',
       }),
     })
 
@@ -217,7 +208,6 @@ describe('EventCreateView', () => {
       organizerToken: 'org-456',
       title: 'Birthday Party',
       dateTime: '2026-12-25T18:00:00+01:00',
-      expiryDate: '2026-12-24',
     })
 
     expect(pushSpy).toHaveBeenCalledWith({
@@ -245,7 +235,6 @@ describe('EventCreateView', () => {
 
     await wrapper.find('#title').setValue('Duplicate Event')
     await wrapper.find('#dateTime').setValue('2026-12-25T18:00')
-    await wrapper.find('#expiryDate').setValue('2026-12-24')
 
     await wrapper.find('form').trigger('submit')
     await flushPromises()
@@ -256,6 +245,5 @@ describe('EventCreateView', () => {
 
     // Other field errors should not be present
     expect(wrapper.find('#dateTime-error').exists()).toBe(false)
-    expect(wrapper.find('#expiryDate-error').exists()).toBe(false)
   })
 })

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

@@ -54,7 +54,6 @@ const fullEvent = {
   timezone: 'Europe/Berlin',
   location: 'Central Park, NYC',
   attendeeCount: 12,
-  expired: false,
 }
 
 function mockLoadedEvent(eventOverrides = {}) {
@@ -124,29 +123,6 @@ describe('EventDetailView', () => {
     wrapper.unmount()
   })
 
-  // Expired state
-  it('renders "event has ended" banner when expired', async () => {
-    mockLoadedEvent({ expired: true })
-
-    const wrapper = await mountWithToken()
-    await flushPromises()
-
-    expect(wrapper.text()).toContain('This event has ended.')
-    expect(wrapper.find('.detail__banner--expired').exists()).toBe(true)
-    wrapper.unmount()
-  })
-
-  // No expired banner when not expired
-  it('does not render expired banner when event is active', async () => {
-    mockLoadedEvent()
-
-    const wrapper = await mountWithToken()
-    await flushPromises()
-
-    expect(wrapper.find('.detail__banner--expired').exists()).toBe(false)
-    wrapper.unmount()
-  })
-
   // Not found state
   it('renders "event not found" when API returns 404', async () => {
     vi.mocked(api.GET).mockResolvedValue({
@@ -229,17 +205,6 @@ describe('EventDetailView', () => {
     wrapper.unmount()
   })
 
-  it('does not show RSVP bar on expired event', async () => {
-    mockLoadedEvent({ expired: true })
-
-    const wrapper = await mountWithToken()
-    await flushPromises()
-
-    expect(wrapper.find('.rsvp-bar__cta').exists()).toBe(false)
-    expect(wrapper.find('.rsvp-bar').exists()).toBe(false)
-    wrapper.unmount()
-  })
-
   it('shows RSVP status bar when localStorage has RSVP', async () => {
     mockGetRsvp.mockReturnValue({ rsvpToken: 'rsvp-1', rsvpName: 'Max' })
     mockLoadedEvent()