curl --request POST \
  --url https://api.mixpeek.com/v1/namespaces/migrations/ \
  --header 'Content-Type: application/json' \
  --data '
{
  "config": {
    "feature_extractors": [
      {
        "feature_extractor_name": "openai_text_embedding",
        "parameters": {
          "model": "text-embedding-3-large"
        },
        "version": "v3"
      }
    ],
    "migration_type": "re_extract",
    "source_namespace_id": "ns_abc123",
    "target_namespace_name": "my_namespace_v2"
  },
  "start_immediately": false
}
'

{
  "created_at": "2025-12-03T10:00:00Z",
  "message": "Migration created successfully. Use POST /migrations/{id}/start to begin execution.",
  "migration_id": "mig_abc123xyz789",
  "status": "draft",
  "validation_result": {
    "errors": [],
    "estimated_duration_seconds": 1800,
    "estimated_resources": {
      "cluster": 1,
      "collection": 5,
      "taxonomy": 2
    },
    "valid": true,
    "warnings": []
  }
}