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-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,