feat: notifications in the app and, optionally, by e-mail

Derived from events and kept per person: whoever a ticket is assigned to,
whoever reports or works on it when it moves, fails QA or gets a comment,
and whoever joins a project. Never about what you did yourself, once per
event. They arrive live through a subscription to a bell in the header,
and are copied by e-mail to whoever turns it on when SMTP_URL is set.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/tracker/application/src/lib/tracker-application.module.ts

@@ -16,6 +16,27 @@ import { ReadAccess } from './queries/read-access';
 import { ReleasesService } from './releases.service';
 import { SAGAS } from './sagas/sagas';
 import { WorkflowsService } from './workflows.service';
+import { NotificationsService } from './notifications.service';
+import { Notifier } from './notifications/notifier';
+import { NotificationsEventHandler } from './notifications/notifications.event-handler';
+import {
+  GetMyNotificationSettingsQueryHandler,
+  GetMyNotificationsQueryHandler,
+} from './notifications/notifications.queries';
+import {
+  MarkNotificationsReadCommandHandler,
+  UpdateNotificationSettingsCommandHandler,
+} from './notifications/notifications.commands';
+
+/** Notifications: derived from events, kept and dismissed per person. */
+const NOTIFICATIONS = [
+  Notifier,
+  NotificationsEventHandler,
+  GetMyNotificationsQueryHandler,
+  GetMyNotificationSettingsQueryHandler,
+  MarkNotificationsReadCommandHandler,
+  UpdateNotificationSettingsCommandHandler,
+];
 
 const SERVICES = [
   ProjectsService,
@@ -24,6 +45,7 @@ const SERVICES = [
   ReleasesService,
   ChangesService,
   WorkflowsService,
+  NotificationsService,
 ];
 
 /**
@@ -43,6 +65,7 @@ const SERVICES = [
     ...QUERY_HANDLERS,
     ...EVENT_HANDLERS,
     ...SAGAS,
+    ...NOTIFICATIONS,
   ],
   exports: SERVICES,
 })