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/domain/src/lib/events/comment-thread-resolved.event.ts

@@ -0,0 +1,17 @@
+import { AutowiredEvent } from '@task-stream/api/shared/domain';
+import { TrackerEvent } from './tracker.event';
+
+/** A conversation (a top-level comment and its replies) was settled, or reopened. */
+@AutowiredEvent
+export class CommentThreadResolvedEvent extends TrackerEvent {
+  constructor(
+    actorId: string,
+    commentId: string,
+    projectId: string,
+    readonly issueId: string,
+    /** False: reopened. */
+    readonly resolved: boolean,
+  ) {
+    super(actorId, commentId, projectId);
+  }
+}

libs/api/tracker/domain/src/lib/events/index.ts

@@ -16,6 +16,7 @@ export * from './comment-added.event';
 export * from './comment-edited.event';
 export * from './comment-reacted.event';
 export * from './comment-decision-marked.event';
+export * from './comment-thread-resolved.event';
 export * from './comment-deleted.event';
 export * from './release-created.event';
 export * from './release-updated.event';