Retrieve namespace details or root list

Fetches metadata for a specific namespace or lists all available root namespaces. Behavior: - With namespace provided: returns the specified namespace's identifier along with its immediate children, including sub-namespaces, tables, and files. - Without namespace: returns a high-level list of all top-level root namespaces available in the catalog. Example Usage: ```bash curl -X GET '/namespaces' ```

curl -X GET "https://example.com/namespaces"

{
  "success": true,
  "data": {
    "namespaces": [
      "string"
    ]
  }
}

{
  "detail": [
    {
      "loc": [
        null
      ],
      "msg": "string",
      "type": "string",
      "input": "string",
      "ctx": {
        "property1": null,
        "property2": null
      }
    }
  ]
}

{
  "error": "string",
  "error_code": "string"
}

{
  "error": "string",
  "error_code": "string"
}