[Epic 7.1] Define IAutoTradeAdapter interface

[ooples]

User Story

As a library maintainer, I want a clean trading adapter interface so that new broker integrations can be easily added.

Acceptance Criteria

• IAutoTradeAdapter interface with order methods
• TradeOrder record with order details:
  • Symbol
  • Side (Buy/Sell)
  • OrderType (Market/Limit/Stop)
  • Quantity
  • LimitPrice (optional)
  • StopPrice (optional)
  • TimeInForce
• TradeResult for order status
• Async-first design
• Position tracking interface

Interface Design

public interface IAutoTradeAdapter : IAsyncDisposable
{
    string AdapterType { get; }
    bool IsLiveTradingEnabled { get; }
    
    Task<TradeResult> SubmitOrderAsync(TradeOrder order, CancellationToken ct = default);
    Task<Position?> GetPositionAsync(SymbolId symbol, CancellationToken ct = default);
    Task<IReadOnlyList<TradeOrder>> GetOpenOrdersAsync(CancellationToken ct = default);
    Task<bool> CancelOrderAsync(string orderId, CancellationToken ct = default);
}

public record TradeOrder(
    SymbolId Symbol,
    OrderSide Side,
    OrderType Type,
    decimal Quantity,
    decimal? LimitPrice = null,
    decimal? StopPrice = null,
    TimeInForce TimeInForce = TimeInForce.Day);

Dependencies

• [Epic 5.1] Create SignalCatalog