fix(transport): carry Transport + OAuth2 authority/scope on SmtpConfigDto (OAuth2 fields were silently dropped)

src/ZB.MOM.WW.ScadaBridge.Transport/Serialization/EntitySerializer.cs

@@ -186,7 +186,12 @@ public sealed class EntitySerializer
                     MaxConcurrentConnections: smtp.MaxConcurrentConnections,
                     MaxRetries: smtp.MaxRetries,
                     RetryDelay: smtp.RetryDelay,
-                    Secrets: secrets);
+                    Secrets: secrets,
+                    // Non-sensitive delivery metadata: the OAuth2 endpoint pair and
+                    // the Smtp/Ews transport selector travel as plain DTO fields.
+                    OAuth2Authority: smtp.OAuth2Authority,
+                    OAuth2Scope: smtp.OAuth2Scope,
+                    Transport: smtp.Transport);
             }).ToList(),
             // Inbound API keys are not transported between environments:
             // the bundle carries API methods only. ApiMethod.ApprovedApiKeyIds is also
@@ -486,6 +491,11 @@ public sealed class EntitySerializer
                 MaxConcurrentConnections = dto.MaxConcurrentConnections,
                 MaxRetries = dto.MaxRetries,
                 RetryDelay = dto.RetryDelay,
+                // Null on a bundle written before these fields were carried, which
+                // is exactly the entity's "use the provider defaults / Smtp" state.
+                OAuth2Authority = dto.OAuth2Authority,
+                OAuth2Scope = dto.OAuth2Scope,
+                Transport = dto.Transport,
             })
             .ToList();