List custom skills

curl --request GET \
  --url https://api.case.dev/skills/custom \
  --header 'Authorization: Bearer <token>'

{
  "skills": [
    {
      "slug": "<string>",
      "name": "<string>",
      "summary": "<string>",
      "tags": [
        "<string>"
      ],
      "metadata": {},
      "version": 123,
      "created_at": "2023-11-07T05:31:56Z",
      "updated_at": "2023-11-07T05:31:56Z"
    }
  ],
  "next_cursor": "<string>",
  "has_more": true
}