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/web/tracker/infrastructure/src/lib/adapters/graphql-collaboration.gateways.ts

@@ -24,6 +24,7 @@ import {
   IssueCommentsDocument,
   ReactToCommentDocument,
   MarkDecisionDocument,
+  ResolveThreadDocument,
   PublishReleaseDocument,
   ReleaseBurnupDocument,
   ReleaseNotesDraftDocument,
@@ -77,6 +78,16 @@ export class GraphqlCommentsGateway extends CommentsGateway {
       .pipe(map((d) => toCommandResult(d.deleteComment)));
   }
 
+  resolveThread(
+    commentId: string,
+    resolved: boolean,
+    conclusion: string | null,
+  ): Observable<CommandResult> {
+    return this.gql
+      .mutate(ResolveThreadDocument, { commentId, resolved, conclusion })
+      .pipe(map((d) => toCommandResult(d.resolveThread)));
+  }
+
   markDecision(commentId: string, on: boolean): Observable<CommandResult> {
     return this.gql
       .mutate(MarkDecisionDocument, { commentId, on })