add permission to suppliers

backend/prisma/schema.prisma

@@ -1624,3 +1624,12 @@ model Approval {
   @@map("approvals")
 }
 
+model SystemSetting {
+  key       String   @id
+  value     String
+  category  String   @default("general")
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+
+  @@map("system_settings")
+}