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

src/Router/__Libraries/StellaOps.Router.Gateway/OpenApi/OpenApiEndpoints.cs

@@ -1,3 +1,4 @@
+using System.Globalization;
 using System.Text.Json.Nodes;
 using Microsoft.AspNetCore.Mvc;
 using YamlDotNet.Serialization;
@@ -42,7 +43,7 @@ public static class OpenApiEndpoints
             openapi_json = "/openapi.json",
             openapi_yaml = "/openapi.yaml",
             etag,
-            generated_at = generatedAt.ToString("O")
+            generated_at = generatedAt.ToString("O", CultureInfo.InvariantCulture)
         };
 
         context.Response.Headers.CacheControl = "public, max-age=60";