feat: conversations on a ticket are settled, and you see who is typing

A top-level comment and its replies can be resolved by whoever can
change the ticket (CommentThreadResolvedEvent), with an optional
conclusion added as a reply marked as a decision, so it shows above the
ticket. A settled conversation folds to one line (topic, who settled it
and the conclusion) and can be unfolded or reopened; the header counts
the open ones, and finishing the ticket with one open asks first.

«Ana está escribiendo…» shows in the conversation being answered, at
once: a `typing` mutation publishes to a Redis channel per ticket
(`typing` subscription), never stored. In replies, Enter sends and
Shift+Enter breaks the line, except inside lists and code.

API: resolveThread / PUT-DELETE /api/comments/{id}/resolution, Comment
.resolved/resolvedBy/resolvedAt, typing mutation and subscription. MCP:
resolve_thread.

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

libs/api/tracker/application/src/lib/event-handlers/event-handlers.ts

@@ -4,6 +4,7 @@ import { CommentDeletedEventHandler } from './comment-deleted.event-handler';
 import { CommentEditedEventHandler } from './comment-edited.event-handler';
 import { CommentReactedEventHandler } from './comment-reacted.event-handler';
 import { CommentDecisionMarkedEventHandler } from './comment-decision-marked.event-handler';
+import { CommentThreadResolvedEventHandler } from './comment-thread-resolved.event-handler';
 import { IssueVotedEventHandler } from './issue-voted.event-handler';
 import { IssueAssignedEventHandler } from './issue-assigned.event-handler';
 import { IssueCreatedEventHandler } from './issue-created.event-handler';
@@ -52,6 +53,7 @@ export const EVENT_HANDLERS = [
   CommentEditedEventHandler,
   CommentReactedEventHandler,
   CommentDecisionMarkedEventHandler,
+  CommentThreadResolvedEventHandler,
   IssueVotedEventHandler,
   IssueAssignedEventHandler,
   IssueCreatedEventHandler,