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/data-model.md

@@ -0,0 +1,72 @@
+# Data Model: View Attendee List (011)
+
+**Date**: 2026-03-08
+
+## Entities
+
+### Rsvp (existing — no schema changes)
+
+The attendee list feature reads from the existing `rsvps` table. No new tables or columns are required.
+
+| Field | Type | Constraints | Notes |
+|-------|------|-------------|-------|
+| id | BIGSERIAL | PK, auto-increment | Chronological order proxy |
+| rsvp_token | UUID | UNIQUE, NOT NULL | Public identifier |
+| event_id | BIGINT | FK → events.id, NOT NULL | CASCADE DELETE |
+| name | VARCHAR(100) | NOT NULL | Display name shown to organizer |
+
+**Existing indexes**: `idx_rsvps_event_id` (on `event_id`), `idx_rsvps_rsvp_token` (on `rsvp_token`).
+
+### Event (existing — no schema changes)
+
+The `organizer_token` column on the `events` table is used for authorization. The endpoint verifies that the provided organizer token matches the event's stored token.
+
+| Field | Type | Notes |
+|-------|------|-------|
+| organizer_token | UUID | UNIQUE, NOT NULL — used for attendee list authorization |
+
+## Query Patterns
+
+### Get attendees by event token
+
+```sql
+SELECT r.name
+FROM rsvps r
+JOIN events e ON r.event_id = e.id
+WHERE e.event_token = :eventToken
+ORDER BY r.id ASC;
+```
+
+**Performance**: Uses existing `idx_rsvps_event_id` index. Expected result set is small (spec assumes small-to-medium events, no pagination needed).
+
+### Organizer token verification
+
+```sql
+SELECT e.organizer_token
+FROM events e
+WHERE e.event_token = :eventToken;
+```
+
+Already implemented in `EventService.getByEventToken()` — the event entity includes the organizer token. The use case compares the provided token against the stored one.
+
+## Domain Model Changes
+
+### New Outbound Port Method
+
+```java
+// RsvpRepository (existing interface)
+List<Rsvp> findByEventId(Long eventId);  // NEW
+```
+
+### New Inbound Port
+
+```java
+// GetAttendeesUseCase (new interface)
+List<String> getAttendeeNames(EventToken eventToken, OrganizerToken organizerToken);
+```
+
+Returns a list of attendee display names. Throws `EventNotFoundException` if event token is invalid. Throws `AccessDeniedException` (or similar) if organizer token does not match.
+
+## No Migration Required
+
+All required data structures already exist from changeset `003-create-rsvps-table.xml`. This feature only adds read access to existing data.