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/web/tracker/infrastructure/src/lib/adapters/graphql-issues.gateway.ts

@@ -89,6 +89,7 @@ export class GraphqlIssuesGateway extends IssuesGateway {
     return this.gql
       .query(MyIssuesDocument, {
         assignedToMe: filter.assignedToMe,
+        watching: filter.watching ?? false,
         categories: filter.categories as never,
         limit: filter.limit,
         search: filter.search?.trim() || null,