email service and template using resend

prisma/schema.prisma

@@ -467,6 +467,51 @@ model Refund {
   @@index([status, createdAt])
 }
 
+/// Log append-only setiap email yang berhasil terkirim. `idempotencyKey`
+/// UNIQUE cegah double-send saat webhook retry / cron rerun.
+model EmailSent {
+  id                String   @id @default(cuid())
+  idempotencyKey    String   @unique
+  to                String
+  template          String
+  subject           String
+  /// ID dari Resend (atau provider lain) untuk troubleshooting di dashboard mereka.
+  providerMessageId String?
+  sentAt            DateTime @default(now())
+
+  @@index([to, sentAt(sort: Desc)])
+  @@index([template, sentAt(sort: Desc)])
+}
+
+/// Retry queue untuk email yang gagal saat sync send. Cron pick PENDING/FAILED
+/// (attempts<5) → retry dengan exponential backoff. Idempotent via `idempotencyKey`.
+model EmailJob {
+  id              String         @id @default(cuid())
+  idempotencyKey  String
+  to              String
+  template        String
+  subject         String
+  html            String
+  status          EmailJobStatus @default(PENDING)
+  attempts        Int            @default(0)
+  scheduledAt     DateTime       @default(now())
+  lastAttemptAt   DateTime?
+  lastError       String?
+
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@index([status, scheduledAt])
+  @@index([idempotencyKey])
+}
+
+enum EmailJobStatus {
+  PENDING
+  PROCESSING
+  SUCCESS
+  FAILED
+}
+
 /// Log polymorphic untuk admin actions lintas entity. Append-only — kalau
 /// admin dihapus, `adminId` di-set NULL tapi `adminEmail` snapshot tetap.
 /// Dipakai untuk compliance & investigasi (siapa approve/reject/cancel/