Get an app by id or slug

{
  "success": true,
  "app": {
    "id": 1,
    "appId": "k4FqL2Hm",
    "revision": 7,
    "name": "Customer health check",
    "slug": "customer-health-check",
    "description": "string",
    "vendor": "string",
    "availability": "string",
    "appearance": null,
    "data": null,
    "isActive": true,
    "deletedAt": "2026-01-01T12:00:00Z",
    "createdBy": 1,
    "createdAt": "2026-01-01T12:00:00Z"
  }
}