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

src/Cli/StellaOps.Cli/Commands/CommandHandlers.Witness.cs

@@ -5,6 +5,7 @@
 // Description: Command handlers for reachability witness CLI.
 // -----------------------------------------------------------------------------
 
+using System.Globalization;
 using System.Text.Json;
 using Spectre.Console;
 
@@ -46,7 +47,7 @@ internal static partial class CommandHandlers
             PackageName = "Newtonsoft.Json",
             PackageVersion = "12.0.3",
             ConfidenceTier = "confirmed",
-            ObservedAt = DateTimeOffset.UtcNow.AddHours(-2).ToString("O"),
+            ObservedAt = DateTimeOffset.UtcNow.AddHours(-2).ToString("O", CultureInfo.InvariantCulture),
             Entrypoint = new WitnessEntrypointDto
             {
                 Type = "http",