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>

specs/011-view-attendee-list/quickstart.md

@@ -0,0 +1,76 @@
+# Quickstart: View Attendee List (011)
+
+## Prerequisites
+
+- Java 25 (SDKMAN)
+- Node.js 20+ / npm
+- PostgreSQL running (or Docker for Testcontainers)
+
+## Development Flow
+
+### 1. Update OpenAPI spec
+
+Edit `backend/src/main/resources/openapi/api.yaml` to add the `GET /events/{token}/attendees` endpoint and response schemas (see `contracts/api.md`).
+
+### 2. Generate types
+
+```bash
+# Backend: regenerate Spring interfaces
+cd backend && ./mvnw compile
+
+# Frontend: regenerate TypeScript types
+cd frontend && npm run generate:api
+```
+
+### 3. Backend implementation (TDD)
+
+```bash
+# Write tests first
+cd backend && ./mvnw test
+
+# Run specific test class
+cd backend && ./mvnw test -Dtest=EventControllerIntegrationTest
+cd backend && ./mvnw test -Dtest=RsvpServiceTest
+```
+
+### 4. Frontend implementation (TDD)
+
+```bash
+# Unit tests
+cd frontend && npm run test:unit
+
+# E2E tests
+cd frontend && npx playwright test e2e/view-attendee-list.spec.ts
+```
+
+### 5. Verify
+
+```bash
+# Backend full verify (includes checkstyle)
+cd backend && ./mvnw verify
+
+# Frontend build check
+cd frontend && npm run build
+```
+
+## Key Files to Modify
+
+| Layer | File | Change |
+|-------|------|--------|
+| API Spec | `backend/src/main/resources/openapi/api.yaml` | Add endpoint + schemas |
+| Port (in) | `de.fete.domain.port.in.GetAttendeesUseCase` | New interface |
+| Port (out) | `de.fete.domain.port.out.RsvpRepository` | Add `findByEventId` |
+| Service | `de.fete.application.service.RsvpService` | Implement use case |
+| Persistence | `de.fete.adapter.out.persistence.RsvpJpaRepository` | Add query method |
+| Persistence | `de.fete.adapter.out.persistence.RsvpPersistenceAdapter` | Implement port method |
+| Controller | `de.fete.adapter.in.web.EventController` | Add endpoint handler |
+| Frontend | `src/views/EventDetailView.vue` | Integrate AttendeeList |
+| Frontend | `src/components/AttendeeList.vue` | New component |
+
+## Testing Checklist
+
+- [ ] Backend unit test: `RsvpService.getAttendeeNames` — valid token, invalid token, no RSVPs
+- [ ] Backend integration test: `GET /events/{token}/attendees` — 200, 403, 404
+- [ ] Frontend unit test: `AttendeeList.vue` — renders names, empty state, loading
+- [ ] Frontend unit test: `EventDetailView.vue` — shows list for organizer, hides for visitor
+- [ ] E2E test: organizer sees attendee names, visitor sees count only