refactor(dotnet): move collection schema init to service

src/dotnet/QuantEngine.Core/Interfaces/IDataCollectionStore.cs

@@ -63,6 +63,11 @@ public interface ICollectionReadRepository
     Task<List<PriceHistorySummaryRecord>> GetPriceHistorySummaryAsync();
 }
 
+public interface ICollectionSchemaInitializer
+{
+    Task InitializeAsync();
+}
+
 /// <summary>
 /// Collection run record (maps Python CollectionRun).
 /// </summary>