feat(backend): Benachrichtigungssystem (Modul 26)

NotificationsModule: Notification-Modell mit Prioritaeten INFO/
HINWEIS/WARNUNG/KRITISCH, GET /notifications (eigene + Broadcast),
POST /notifications/:id/read. record() als interne API fuer
kuenftige Automatisierungsregeln (Modul 30) vorgesehen.

ApiCore-Backend/prisma/schema.prisma

@@ -50,6 +50,7 @@ model User {
   colonyMoves        ColonyApiaryHistory[]
   auditLogs          AuditLog[]
   bottlingBatches    BottlingBatch[]
+  notifications      Notification[]
 
   @@index([role])
 }
@@ -698,3 +699,29 @@ model Equipment {
 
   @@index([condition])
 }
+
+// ---------------------------------------------------------------------------
+// Benachrichtigungssystem (Abschnitt 24) – v1.x Modul 26
+// ---------------------------------------------------------------------------
+
+enum NotificationPriority {
+  INFO
+  HINWEIS
+  WARNUNG
+  KRITISCH
+}
+
+model Notification {
+  id          String               @id @default(cuid())
+  userId      String?
+  user        User?                @relation(fields: [userId], references: [id])
+  priority    NotificationPriority
+  message     String
+  relatedType String?
+  relatedId   String?
+  read        Boolean              @default(false)
+  createdAt   DateTime             @default(now())
+
+  @@index([userId, read])
+  @@index([priority])
+}