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/presenters/src/lib/http/comments.controller.ts

@@ -17,7 +17,11 @@ import {
 import { ApiCommandErrors } from '@task-stream/api/shared/presenters';
 import { CommentsService } from '@task-stream/api/tracker/application';
 import { REACTIONS } from '@task-stream/api/tracker/domain';
-import { CommentBodyDto, ReactToCommentDto } from './dto/requests.dto';
+import {
+  CommentBodyDto,
+  ReactToCommentDto,
+  ResolveThreadDto,
+} from './dto/requests.dto';
 import { CommandResultDto } from './dto/responses.dto';
 
 /** REST adapter of the comment use cases (listing and adding live under /issues). */
@@ -78,6 +82,35 @@ export class CommentsController {
     return this.comments.markDecision(me.id, commentId, false);
   }
 
+  @Put(':commentId/resolution')
+  @ApiOperation({
+    summary: 'Settle a conversation (a top-level comment and its replies)',
+    description:
+      'Whoever can change the ticket. A conclusion is added as a reply marked as a decision. The web folds a settled conversation.',
+  })
+  @ApiOkResponse({ type: CommandResultDto })
+  @ApiCommandErrors()
+  resolveThread(
+    @CurrentUser() me: User,
+    @Param('commentId') commentId: string,
+    @Body() body: ResolveThreadDto,
+  ) {
+    return this.comments.resolveThread(
+      me.id,
+      commentId,
+      true,
+      body.conclusion ?? null,
+    );
+  }
+
+  @Delete(':commentId/resolution')
+  @ApiOperation({ summary: 'Reopen a conversation' })
+  @ApiOkResponse({ type: CommandResultDto })
+  @ApiCommandErrors()
+  reopenThread(@CurrentUser() me: User, @Param('commentId') commentId: string) {
+    return this.comments.resolveThread(me.id, commentId, false);
+  }
+
   @Delete(':commentId')
   @ApiOperation({ summary: 'Delete a comment (author or project admin)' })
   @ApiOkResponse({ type: CommandResultDto })