List externally-sourced skills in your registries

{  "items": [    {      "sourceKind": "github",      "sourceUrl": "string",      "skillName": "string",      "registry": {        "ownerHandle": "string",        "slug": "string"      }    }  ],  "nextCursor": "string"}

{  "defined": true,  "code": "UNAUTHORIZED",  "status": 401,  "message": "Authentication required or credentials invalid.",  "data": null}

{  "defined": true,  "code": "VALIDATION",  "status": 422,  "message": "The input failed domain validation.",  "data": {    "issues": [      {        "path": "string",        "message": "string"      }    ]  }}

{  "defined": true,  "code": "RATE_LIMITED",  "status": 429,  "message": "Rate limit exceeded; retry later.",  "data": {    "retryAfterSeconds": -9007199254740991  }}