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/presenters/src/lib/http/issues.controller.ts

@@ -128,6 +128,7 @@ export class IssuesController {
   async mine(@CurrentUser() me: User, @Query() query: MyIssuesQueryDto) {
     const page = await this.issues.mine(me.id, {
       assignedToMe: query.assignedToMe,
+      watching: query.watching,
       statuses: query.status,
       categories: query.category,
       search: query.search,
@@ -164,6 +165,7 @@ export class IssuesController {
       labels: query.label,
       sprintId: query.sprintId,
       noSprint: query.noSprint,
+      watching: query.watching,
       dueFrom: query.dueFrom,
       dueTo: query.dueTo,
       sort: query.sort,