feat(notifications): no-SDK EWS SOAP mail sender with typed transient/permanent classification

src/ZB.MOM.WW.ScadaBridge.NotificationService/ServiceCollectionExtensions.cs

@@ -1,15 +1,17 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Options;
+using ZB.MOM.WW.ScadaBridge.NotificationService.Ews;
 
 namespace ZB.MOM.WW.ScadaBridge.NotificationService;
 
 public static class ServiceCollectionExtensions
 {
     /// <summary>
-    /// Registers the shared SMTP delivery primitives consumed by the central Notification
+    /// Registers the shared email delivery primitives consumed by the central Notification
     /// Outbox's <c>EmailNotificationDeliveryAdapter</c>: <see cref="NotificationOptions"/>,
-    /// <see cref="OAuth2TokenService"/>, and the <see cref="ISmtpClientWrapper"/> factory.
+    /// <see cref="OAuth2TokenService"/>, the <see cref="ISmtpClientWrapper"/> factory, and —
+    /// for the EWS transport — <see cref="IEwsMailSender"/> with its named HTTP client.
     /// Central-only — sites no longer deliver notifications (see
     /// <c>Component-NotificationService.md</c>), and the orphaned site-shaped
     /// <c>NotificationDeliveryService</c> + <c>INotificationDeliveryService</c> contract
@@ -30,6 +32,11 @@ public static class ServiceCollectionExtensions
         services.AddSingleton<OAuth2TokenService>();
         services.AddSingleton<Func<ISmtpClientWrapper>>(_ => () => new MailKitSmtpClientWrapper());
 
+        // EWS transport: a named client so the EWS calls get their own handler pool, and a
+        // stateless singleton sender (credentials travel per request, never on the client).
+        services.AddHttpClient(EwsSoapMailSender.HttpClientName);
+        services.TryAddSingleton<IEwsMailSender, EwsSoapMailSender>();
+
         return services;
     }