Get portfolio performance

curl --request GET \
  --url https://api.bluumfinance.com/v1/wealth/accounts/{account_id}/portfolios/{portfolio_id}/performance \
  --header 'Authorization: Basic <encoded-value>'

{
  "portfolio_id": "port_a1b2c3d4e5f6",
  "period": {
    "start_date": "2024-01-15",
    "end_date": "2025-01-15",
    "label": "1y"
  },
  "returns": {
    "time_weighted_return": "12.50",
    "money_weighted_return": "11.80",
    "total_return": "15000.00",
    "annualized_return": "12.50"
  },
  "benchmark_comparison": {
    "benchmark_symbol": "SPY",
    "benchmark_name": "S&P 500 ETF",
    "benchmark_return": "10.20",
    "alpha": "2.30",
    "tracking_error": "3.50"
  },
  "risk_metrics": {
    "volatility": "14.50",
    "sharpe_ratio": "0.86",
    "max_drawdown": "-8.20",
    "max_drawdown_date": "2024-08-05",
    "beta": "0.95"
  },
  "period_breakdown": {
    "starting_value": "100000.00",
    "ending_value": "125000.00",
    "net_contributions": "10000.00",
    "net_withdrawals": "0.00",
    "investment_gains": "15000.00",
    "dividends_received": "2500.00",
    "fees_paid": "250.00"
  },
  "value_history": [
    {
      "date": "2024-01-15",
      "value": "100000.00"
    },
    {
      "date": "2024-07-15",
      "value": "110000.00"
    },
    {
      "date": "2025-01-15",
      "value": "125000.00"
    }
  ]
}