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/dto/responses.dto.ts

@@ -642,6 +642,19 @@ export class CommentDto {
   decidedBy!: UserRefDto | null;
   @ApiProperty({ type: String, nullable: true, format: 'date-time' })
   decidedAt!: string | null;
+  @ApiProperty({
+    description:
+      'A conversation (top-level comment and its replies) that was settled',
+  })
+  resolved!: boolean;
+  @ApiProperty({
+    type: UserRefDto,
+    nullable: true,
+    description: 'Who settled it',
+  })
+  resolvedBy!: UserRefDto | null;
+  @ApiProperty({ type: String, nullable: true, format: 'date-time' })
+  resolvedAt!: string | null;
   @ApiProperty({ format: 'date-time' }) createdAt!: string;
   @ApiProperty({ type: String, nullable: true, format: 'date-time' })
   editedAt!: string | null;