feat: quick polls in comments that end in a decision

«📊 Añadir una encuesta» adds 2 to 6 options to a new comment. Members,
viewers too, vote by clicking an option (one vote each, which they can
change or take back) and see each option's votes as a bar. Whoever
started it, or an admin, closes it with «Cerrar y decidir»: the most
voted wins (none on a tie) and a «Decidido: …» reply marked as a
decision shows above the ticket. Events of the comment (voted, closed).

API: addComment(…, poll), votePoll, closePoll, Comment.poll;
POST /api/comments/{id}/poll/vote and …/poll/close. MCP: add_comment
poll, vote_poll, close_poll.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/tracker/presenters/src/lib/http/dto/responses.dto.ts

@@ -612,6 +612,22 @@ export class CommentReactionDto {
   @ApiProperty({ type: [UserRefDto] }) users!: UserRefDto[];
 }
 
+export class PollOptionDto {
+  @ApiProperty() text!: string;
+  @ApiProperty({ type: [UserRefDto] }) voters!: UserRefDto[];
+}
+
+export class CommentPollDto {
+  @ApiProperty({ type: [PollOptionDto] }) options!: PollOptionDto[];
+  @ApiProperty() closed!: boolean;
+  @ApiProperty({
+    type: Number,
+    nullable: true,
+    description: 'Index of the winning option once closed (null on a tie)',
+  })
+  winner!: number | null;
+}
+
 export class CommentDto {
   @ApiProperty({ format: 'uuid' }) id!: string;
   @ApiProperty({ format: 'uuid' }) issueId!: string;
@@ -648,6 +664,8 @@ export class CommentDto {
   decidedBy!: UserRefDto | null;
   @ApiProperty({ type: String, nullable: true, format: 'date-time' })
   decidedAt!: string | null;
+  @ApiProperty({ type: CommentPollDto, nullable: true })
+  poll!: CommentPollDto | null;
   @ApiProperty({
     description:
       'A conversation (top-level comment and its replies) that was settled',