save work

src/__Libraries/StellaOps.Infrastructure.Postgres/Repositories/RepositoryBase.cs

@@ -1,3 +1,4 @@
+using System.Globalization;
 using System.Runtime.CompilerServices;
 using System.Text;
 using Microsoft.Extensions.Logging;
@@ -234,7 +235,30 @@ public abstract class RepositoryBase<TDataSource> where TDataSource : DataSource
         configureCommand?.Invoke(command);
 
         var result = await command.ExecuteScalarAsync(cancellationToken).ConfigureAwait(false);
-        return result is DBNull or null ? default : (T)result;
+        if (result is DBNull or null)
+        {
+            return default;
+        }
+
+        if (result is T typed)
+        {
+            return typed;
+        }
+
+        var targetType = typeof(T);
+        var underlyingTargetType = Nullable.GetUnderlyingType(targetType) ?? targetType;
+
+        try
+        {
+            var converted = Convert.ChangeType(result, underlyingTargetType, CultureInfo.InvariantCulture);
+            return (T?)converted;
+        }
+        catch (Exception ex) when (ex is InvalidCastException or FormatException or OverflowException)
+        {
+            throw new InvalidCastException(
+                $"Failed to convert scalar result ({result.GetType().FullName}) to {targetType.FullName} in {callerName ?? "unknown"}.",
+                ex);
+        }
     }
 
     /// <summary>