Update position value calculations in AgentGrain and BotService

- Changed the calculation of USDC value in AgentGrain to use net profit and loss instead of realized profit.
- Added similar position value calculations in BotService, including error handling for position retrieval failures.

src/Managing.Application/Bots/Grains/AgentGrain.cs

@@ -214,8 +214,8 @@ public class AgentGrain : Grain, IAgentGrain
                 foreach (var position in positions.Where(p => p.IsOpen()))
                 {
                     var positionUsd = position.Open.Price * position.Open.Quantity;
-                    var realized = position.ProfitAndLoss?.Realized ?? 0;
-                    usdcInPositionsValue += positionUsd + realized;
+                    var net = position.ProfitAndLoss?.Net ?? 0;
+                    usdcInPositionsValue += positionUsd + net;
                 }
 
                 totalBalance = usdcWalletValue + usdcInPositionsValue;