feat: member portal Sprint 4 — Events + RSVP

- Event + EventRsvp models + migration (RsvpStatus enum: GOING/MAYBE/NOT_GOING)
- EventsModule: admin CRUD (create/update/delete/publish) + RSVP list
- GET /my/events + POST /my/events/:id/rsvp in MyController/MyService
- Admin BFF routes: GET/POST /api/admin/events, PATCH/DELETE /api/admin/events/[id]
- Member BFF routes: GET /api/my/events, POST /api/my/events/[id]/rsvp
- /my/events page: upcoming/past split, RSVP button (client component, optimistic)
- Register DigestModule, OrgModule, ThreadsModule, EventsModule in AppModule
- Add EVENT_CREATED/DELETED/UPDATED and DIGEST_SENT to AuditAction

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

apps/api/prisma/schema.prisma

@@ -90,6 +90,7 @@ model Tenant {
   groupAccesses  GroupAccess[]
   digestConfig   DigestConfig?
   digests        Digest[]
+  events         Event[]
 }
 
 enum AdminRole {
@@ -387,6 +388,7 @@ model TowerUser {
   optOuts  MemberOptOut[]
   sessions TowerSession[]
   messages Message[]      @relation("senderTowerUser")
+  rsvps    EventRsvp[]
 
   @@unique([tenantId, phoneHash])
   @@index([phoneHash])
@@ -528,3 +530,48 @@ model Digest {
   @@unique([tenantId, digestDate])
   @@index([tenantId])
 }
+
+// ============================================================================
+// Events + RSVP
+// ============================================================================
+
+enum RsvpStatus {
+  GOING
+  NOT_GOING
+  MAYBE
+}
+
+model Event {
+  id          String   @id @default(cuid())
+  tenantId    String
+  tenant      Tenant   @relation(fields: [tenantId], references: [id])
+  title       String
+  description String?
+  location    String?
+  startsAt    DateTime
+  endsAt      DateTime?
+  createdBy   String
+  isPublished Boolean  @default(false)
+  createdAt   DateTime @default(now())
+  updatedAt   DateTime @updatedAt
+
+  rsvps EventRsvp[]
+
+  @@index([tenantId, startsAt])
+  @@index([tenantId, isPublished])
+}
+
+model EventRsvp {
+  id        String     @id @default(cuid())
+  eventId   String
+  event     Event      @relation(fields: [eventId], references: [id], onDelete: Cascade)
+  userId    String
+  user      TowerUser  @relation(fields: [userId], references: [id])
+  status    RsvpStatus
+  note      String?
+  createdAt DateTime   @default(now())
+  updatedAt DateTime   @updatedAt
+
+  @@unique([eventId, userId])
+  @@index([userId])
+}