curl --request GET \
 --url https://api.caret.so/v1/folders \
 --header 'Authorization: Bearer <your_api_key>'

{
  "folders": [
    {
      "id": "fld_123456789",
      "name": "Project Alpha",
      "icon": "📁",
      "parentFolderId": null,
      "createdAt": "2024-01-28T12:00:00Z",
      "memberCount": 5
    },
    {
      "id": "fld_987654321",
      "name": "Research",
      "icon": "🔍",
      "parentFolderId": "fld_123456789",
      "createdAt": "2024-01-28T12:30:00Z",
      "memberCount": 3
    }
  ]
}

{
  "error": {
    "code": "unauthorized",
    "message": "Invalid or missing API key"
  }
}

{
  "error": {
    "code": "internal_server_error",
    "message": "Failed to fetch folders"
  }
}