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/changes.service.ts

@@ -9,6 +9,7 @@ import {
   ProjectChange,
   ReleaseChange,
   SprintChange,
+  Typing,
 } from './ports/change-feed';
 import { CanViewProjectQuery } from './queries/can-view-project.query';
 import { GetIssueQuery } from './queries/get-issue.query';
@@ -53,6 +54,15 @@ export class ChangesService {
     return this.changeFeed.comments(issueId);
   }
 
+  /** Who is writing on the ticket (the client leaves itself out). */
+  async watchTyping(
+    viewerId: string,
+    issueId: string,
+  ): Promise<AsyncIterableIterator<Typing>> {
+    await this.queryBus.execute(new GetIssueQuery(viewerId, issueId)); // access check
+    return this.changeFeed.typing(issueId);
+  }
+
   async watchActivity(
     viewerId: string,
     projectId: string,