curl --request GET \
  --url https://synthesis.trade/api/v1/kalshi/user/{username}

{
  "success": true,
  "response": {
    "profile": {
      "username": "top_trader",
      "bio": "Macro and crypto trader",
      "joined_at": "2026-01-01T00:00:00"
    },
    "metrics": {
      "volume": 5000000,
      "profit": 250000,
      "markets_traded": 420
    }
  }
}