Add volume history to platform summary

src/Managing.Application.Abstractions/Grains/IPlatformSummaryGrain.cs

@@ -39,6 +39,11 @@ public interface IPlatformSummaryGrain : IGrainWithStringKey
     /// </summary>
     Task<int> GetTotalPositionCountAsync();
     
+    /// <summary>
+    /// Gets the daily volume history for the last 30 days for chart visualization
+    /// </summary>
+    Task<List<VolumeHistoryPoint>> GetVolumeHistoryAsync();
+    
     // Event handlers for immediate updates
     /// <summary>
     /// Updates the active strategy count

src/Managing.Application.Abstractions/Grains/PlatformSummaryGrainState.cs

@@ -130,3 +130,5 @@ public class DailySnapshot
     [Id(6)]
     public int TotalPositionCount { get; set; }
 }
+
+