Create a namespace

curl --request POST \
  --url https://api.deyta.ai/gateway/v1/namespaces \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "<string>",
  "description": "<string>",
  "external_reference_id": "<string>"
}
'

{
  "success": true,
  "data": {
    "id": "ns_abc123",
    "org_id": "org_xyz789",
    "name": "customer-support",
    "mcp_endpoint_url": "https://api.deyta.ai/mcp/ns_abc123",
    "created_at": "2025-01-15T10:30:00.000Z",
    "updated_at": "2025-01-15T10:30:00.000Z",
    "description": "Customer support knowledge base",
    "external_reference_id": "ext_ref_001"
  }
}