feat: tickets I follow, and more news for followers

"Que sigo" on the home page lists the open tickets I follow, whoever
works on them; `watching` filters my issues (REST, GraphQL, MCP) and a
project's search (none without a session).

Followers now also hear when a ticket's priority or due date changes,
and when it enters or leaves a sprint. Smaller edits (title, labels…)
still do not notify.

Docs (with the REPLIED row the replies change missed), Word and PDF
updated.

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

libs/api/tracker/application/src/lib/notifications/notifications.event-handler.ts

@@ -3,7 +3,10 @@ import {
   CommentAddedEvent,
   IssueAssignedEvent,
   IssueCreatedEvent,
+  IssuePriority,
+  IssueSprintChangedEvent,
   IssueStatusChangedEvent,
+  IssueUpdatedEvent,
   mentionedUserIds,
   NotificationKind,
   ProjectMemberAddedEvent,
@@ -14,11 +17,30 @@ import {
 import { FindCommentsRepository } from '../ports/find-comments.repository';
 import { FindIssuesRepository } from '../ports/find-issues.repository';
 import { FindProjectsRepository } from '../ports/find-projects.repository';
+import { FindSprintsRepository } from '../ports/find-sprints.repository';
 import { UserDirectory } from '../ports/user-directory';
 import { NotificationDraft, Notifier } from './notifier';
 
 /* Read by people, like the activity feed: Spanish. */
 
+/** Same labels as the web app. */
+const PRIORITY: Record<IssuePriority, string> = {
+  [IssuePriority.CRITICAL]: 'Crítica',
+  [IssuePriority.HIGH]: 'Alta',
+  [IssuePriority.MEDIUM]: 'Media',
+  [IssuePriority.LOW]: 'Baja',
+  [IssuePriority.LOWEST]: 'Mínima',
+};
+
+/** 2026-11-14 → 14 de noviembre de 2026. */
+const day = (date: string) =>
+  new Date(`${date.slice(0, 10)}T00:00:00Z`).toLocaleDateString('es-ES', {
+    day: 'numeric',
+    month: 'long',
+    year: 'numeric',
+    timeZone: 'UTC',
+  });
+
 const excerpt = (text: string, max = 120) => {
   const flat = withoutMentionMarkup(text).replace(/\s+/g, ' ').trim();
   return flat.length > max ? `${flat.slice(0, max - 1)}…` : flat;
@@ -35,6 +57,8 @@ const excerpt = (text: string, max = 120) => {
   IssueCreatedEvent,
   IssueAssignedEvent,
   IssueStatusChangedEvent,
+  IssueUpdatedEvent,
+  IssueSprintChangedEvent,
   CommentAddedEvent,
   ProjectMemberAddedEvent,
 )
@@ -45,6 +69,7 @@ export class NotificationsEventHandler implements IEventHandler<TrackerEvent> {
     private readonly findProjects: FindProjectsRepository,
     private readonly users: UserDirectory,
     private readonly findComments: FindCommentsRepository,
+    private readonly findSprints: FindSprintsRepository,
   ) {}
 
   async handle(event: TrackerEvent): Promise<void> {
@@ -183,6 +208,14 @@ export class NotificationsEventHandler implements IEventHandler<TrackerEvent> {
       }
     }
 
+    // Followers also hear of the changes that move their plans.
+    const news = await this.followerNews(event, actor, ticket);
+    if (news) {
+      for (const userId of watcherIds) {
+        drafts.push({ userId, kind: NotificationKind.WATCHED, summary: news });
+      }
+    }
+
     await this.notifier.deliver(
       event,
       {
@@ -194,4 +227,34 @@ export class NotificationsEventHandler implements IEventHandler<TrackerEvent> {
       drafts,
     );
   }
+
+  /**
+   * What a follower should hear of a change of priority, due date or
+   * sprint; null for the other edits (title, labels…), too small to tell.
+   */
+  private async followerNews(
+    event: TrackerEvent,
+    actor: string,
+    ticket: string,
+  ): Promise<string | null> {
+    if (event instanceof IssueUpdatedEvent) {
+      const { priority, dueDate } = event.changes;
+      const parts: string[] = [];
+      if (priority) parts.push(`prioridad ${PRIORITY[priority]}`);
+      if (dueDate !== undefined)
+        parts.push(
+          dueDate ? `fecha límite el ${day(dueDate)}` : 'sin fecha límite',
+        );
+      return parts.length
+        ? `${actor} cambió ${ticket}: ${parts.join(', ')}`
+        : null;
+    }
+    if (event instanceof IssueSprintChangedEvent) {
+      if (!event.sprintId)
+        return `${actor} sacó ${ticket} del sprint y lo devolvió al backlog`;
+      const sprint = await this.findSprints.findById(event.sprintId);
+      return `${actor} metió ${ticket} en ${sprint ? `el sprint ${sprint.name}` : 'un sprint'}`;
+    }
+    return null;
+  }
 }