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/queries/search-issues.query-handler.ts

@@ -15,8 +15,12 @@ export class SearchIssuesQueryHandler
 
   async execute(query: SearchIssuesQuery): Promise<Page<IssueReadModel>> {
     await this.access.assertCanView(query.filter.projectId, query.viewerId);
+    const { watching, ...filter } = query.filter;
+    // Someone anonymous follows nothing.
+    if (watching && !query.viewerId) return { items: [], total: 0 };
     return this.findIssues.search({
-      ...query.filter,
+      ...filter,
+      watcherId: watching ? (query.viewerId ?? undefined) : undefined,
       limit: Math.min(query.filter.limit, 200),
     });
   }

libs/api/tracker/application/src/lib/queries/search-my-issues.query-handler.ts

@@ -19,6 +19,7 @@ export class SearchMyIssuesQueryHandler
     return this.findIssues.searchAcross({
       projectIds: projects.map((project) => project.id),
       assigneeId: query.filter.assignedToMe ? query.viewerId : undefined,
+      watcherId: query.filter.watching ? query.viewerId : undefined,
       statuses: query.filter.statuses,
       categories: query.filter.categories,
       search: query.filter.search?.trim().slice(0, 200) || undefined,

libs/api/tracker/application/src/lib/queries/search-my-issues.query.ts

@@ -8,6 +8,8 @@ import { Page } from '../ports/find-issues.repository';
 export interface MyIssuesFilter {
   /** true: assigned to the viewer. false: any ticket of the viewer's projects. */
   assignedToMe: boolean;
+  /** Only the tickets the viewer follows. */
+  watching?: boolean;
   statuses?: string[];
   /** e.g. TODO + IN_PROGRESS + QA = still open, whatever the project calls them. */
   categories?: StatusCategory[];