audit work, fixed StellaOps.sln warnings/errors, fixed tests, sprints work, new advisories

src/Policy/StellaOps.Policy.Engine/IncrementalOrchestrator/IncrementalPolicyOrchestrator.cs

@@ -1,6 +1,7 @@
 using System.Collections.Concurrent;
 using System.Collections.Immutable;
 using System.Diagnostics;
+using System.Globalization;
 using System.Security.Cryptography;
 using System.Text;
 
@@ -396,7 +397,7 @@ public sealed class IncrementalPolicyOrchestrator
     {
         var builder = new StringBuilder();
         builder.Append(tenantId).Append('|');
-        builder.Append(createdAt.ToString("O")).Append('|');
+        builder.Append(createdAt.ToString("O", CultureInfo.InvariantCulture)).Append('|');
 
         foreach (var evt in events.OrderBy(e => e.EventId, StringComparer.Ordinal))
         {