curl -X POST "https://app.talkover.ai/api/v1/campaigns/campaign-uuid/sftp/test-connection" \
  -H "Authorization: Bearer talq_your_environment_token_here"

{
  "success": true,
  "message": "SFTP connection successful",
  "data": {
    "tested_at": "2024-01-15T16:45:00Z",
    "import_path_accessible": true,
    "export_path_accessible": true
  }
}

{
  "success": false,
  "message": "SFTP connection failed",
  "data": {
    "tested_at": "2024-01-15T16:45:00Z",
    "error": "Authentication failed"
  }
}