Balance for bot (#20)

* Add bot balance

* Update amount to trade

* fix initial trading balance

* Update MM modal

* fix backtest

* stop bot if no more balance

* Add constant for minimum trading

* Add constant

src/Managing.Api/Controllers/TradingController.cs

@@ -150,6 +150,7 @@ public class TradingController : BaseController
             PositionInitiator.User,
             DateTime.UtcNow,
             user,
+            100m, // Default trading balance for user-initiated trades
             isForPaperTrading: isForPaperTrading,
             price: openPrice);
         var result = await _openTradeCommandHandler.Handle(command);